diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
index d811a90b6b22..28d255149b80 100644
--- a/b2g/app/b2g.js
+++ b/b2g/app/b2g.js
@@ -1011,7 +1011,7 @@ pref("dom.activities.developer_mode_only", "import-app");
 pref("dom.serviceWorkers.enabled", false);
 pref("dom.push.enabled", false);
 
-#if defined(RELEASE_BUILD)
+#if defined(RELEASE_OR_BETA)
 // Bug 1278848: Enable service worker notifications on release B2G once
 // they're ready.
 pref("dom.webnotifications.serviceworker.enabled", false);
diff --git a/browser/app/profile/firefox.js b/browser/app/profile/firefox.js
index 1194867930cf..1124b1635845 100644
--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -122,7 +122,7 @@ pref("app.update.auto", true);
 pref("app.update.silent", false);
 
 // If set to true, the hamburger button will show badges for update events.
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 pref("app.update.badge", true);
 #else
 pref("app.update.badge", false);
@@ -328,7 +328,7 @@ pref("browser.download.folderList", 1);
 pref("browser.download.manager.addToRecentDocs", true);
 pref("browser.download.manager.resumeOnWakeDelay", 10000);
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("browser.download.showPanelDropmarker", false);
 #else
 pref("browser.download.showPanelDropmarker", true);
@@ -1244,14 +1244,14 @@ pref("plain_text.wrap_long_lines", true);
 pref("dom.debug.propagate_gesture_events_through_content", false);
 
 // The request URL of the GeoLocation backend.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("geo.wifi.uri", "https://www.googleapis.com/geolocation/v1/geolocate?key=%GOOGLE_API_KEY%");
 #else
 pref("geo.wifi.uri", "https://location.services.mozilla.com/v1/geolocate?key=%MOZILLA_API_KEY%");
 #endif
 
 #ifdef XP_MACOSX
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("geo.provider.use_corelocation", false);
 #else
 pref("geo.provider.use_corelocation", true);
@@ -1264,7 +1264,7 @@ pref("geo.provider.ms-windows-location", false);
 
 #ifdef MOZ_WIDGET_GTK
 #ifdef MOZ_GPSD
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("geo.provider.use_gpsd", false);
 #else
 pref("geo.provider.use_gpsd", true);
@@ -1428,7 +1428,7 @@ pref("privacy.userContext.enabled", false);
 pref("privacy.userContext.ui.enabled", false);
 #endif
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 // At the moment, autostart.2 is used, while autostart.1 is unused.
 // We leave it here set to false to reset users' defaults and allow
 // us to change everybody to true in the future, when desired.
@@ -1447,7 +1447,7 @@ pref("extensions.interposition.enabled", true);
 pref("extensions.interposition.prefetching", true);
 
 // Enable blocking of e10s for add-on users on beta/release.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("extensions.e10sBlocksEnabling", true);
 #endif
 
@@ -1530,7 +1530,7 @@ pref("webchannel.allowObject.urlWhitelist", "https://accounts.firefox.com https:
 // Whether or not the browser should scan for unsubmitted
 // crash reports, and then show a notification for submitting
 // those reports.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("browser.crashReports.unsubmittedCheck.enabled", false);
 #else
 pref("browser.crashReports.unsubmittedCheck.enabled", true);
diff --git a/browser/base/content/browser-devedition.js b/browser/base/content/browser-devedition.js
index dc2f90f65436..5b305b816b03 100644
--- a/browser/base/content/browser-devedition.js
+++ b/browser/base/content/browser-devedition.js
@@ -123,7 +123,7 @@ var DevEdition = {
 // If the DevEdition theme is going to be applied in gBrowserInit.onLoad,
 // then preload it now.  This prevents a flash of unstyled content where the
 // normal theme is applied while the DevEdition stylesheet is loading.
-if (!AppConstants.RELEASE_BUILD &&
+if (!AppConstants.RELEASE_OR_BETA &&
     this != Services.appShell.hiddenDOMWindow && DevEdition.isThemeCurrentlyApplied) {
   DevEdition.createStyleSheet();
 }
diff --git a/browser/components/nsBrowserGlue.js b/browser/components/nsBrowserGlue.js
index 22e0b88b1ed4..f6a9cb3294fa 100644
--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -703,7 +703,7 @@ BrowserGlue.prototype = {
     // Ensure we keep track of places/pw-mananager undo by init'ing this early.
     Cu.import("resource:///modules/AutoMigrate.jsm");
 
-    if (!AppConstants.RELEASE_BUILD) {
+    if (!AppConstants.RELEASE_OR_BETA) {
       let themeName = gBrowserBundle.GetStringFromName("deveditionTheme.name");
       let vendorShortName = gBrandBundle.GetStringFromName("vendorShortName");
 
@@ -1150,7 +1150,7 @@ BrowserGlue.prototype = {
                                              ShellService.shouldCheckDefaultBrowser;
       let promptCount;
       let skipDefaultBrowserCheck = false;
-      if (!AppConstants.RELEASE_BUILD) {
+      if (!AppConstants.RELEASE_OR_BETA) {
         promptCount =
           Services.prefs.getIntPref("browser.shell.defaultBrowserCheckCount");
         skipDefaultBrowserCheck =
@@ -1195,7 +1195,7 @@ BrowserGlue.prototype = {
         }
       }
 
-      if (!AppConstants.RELEASE_BUILD) {
+      if (!AppConstants.RELEASE_OR_BETA) {
         if (willPrompt) {
           Services.prefs.setIntPref("browser.shell.defaultBrowserCheckCount",
                                     promptCount);
diff --git a/build/docs/mozinfo.rst b/build/docs/mozinfo.rst
index 252a83940a1e..d74ca75e6064 100644
--- a/build/docs/mozinfo.rst
+++ b/build/docs/mozinfo.rst
@@ -129,8 +129,8 @@ processor
 
    Always defined.
 
-release_build
-   Whether this is a release build.
+release_or_beta
+   Whether this is a release or beta build.
 
    Values are ``true`` and ``false``.
 
diff --git a/build/moz.configure/init.configure b/build/moz.configure/init.configure
index 99bd5e75dd9e..e17b6ac48378 100644
--- a/build/moz.configure/init.configure
+++ b/build/moz.configure/init.configure
@@ -663,11 +663,11 @@ set_define('MOZ_BUILD_APP', build_project)
 add_old_configure_assignment('MOZ_BUILD_APP', build_project)
 
 
-# set RELEASE_BUILD and NIGHTLY_BUILD variables depending on the cycle we're in
+# set RELEASE_OR_BETA and NIGHTLY_BUILD variables depending on the cycle we're in
 # The logic works like this:
 # - if we have "a1" in GRE_MILESTONE, we're building Nightly (define NIGHTLY_BUILD)
 # - otherwise, if we have "a" in GRE_MILESTONE, we're building Nightly or Aurora
-# - otherwise, we're building Release/Beta (define RELEASE_BUILD)
+# - otherwise, we're building Release/Beta (define RELEASE_OR_BETA)
 @depends(check_build_environment, '--help')
 @imports(_from='__builtin__', _import='open')
 def milestone(build_env, _):
@@ -677,26 +677,26 @@ def milestone(build_env, _):
     with open(milestone_path, 'r') as fh:
         milestone = fh.read().splitlines()[-1]
 
-    is_nightly = is_release = None
+    is_nightly = is_release_or_beta = None
 
     if 'a1' in milestone:
         is_nightly = True
     elif 'a' not in milestone:
-        is_release = True
+        is_release_or_beta = True
 
     return namespace(version=milestone,
                      is_nightly=is_nightly,
-                     is_release=is_release)
+                     is_release_or_beta=is_release_or_beta)
 
 set_config('GRE_MILESTONE', delayed_getattr(milestone, 'version'))
 set_config('NIGHTLY_BUILD', delayed_getattr(milestone, 'is_nightly'))
 set_define('NIGHTLY_BUILD', delayed_getattr(milestone, 'is_nightly'))
 add_old_configure_assignment('NIGHTLY_BUILD',
                              delayed_getattr(milestone, 'is_nightly'))
-set_config('RELEASE_BUILD', delayed_getattr(milestone, 'is_release'))
-set_define('RELEASE_BUILD', delayed_getattr(milestone, 'is_release'))
-add_old_configure_assignment('RELEASE_BUILD',
-                             delayed_getattr(milestone, 'is_release'))
+set_config('RELEASE_OR_BETA', delayed_getattr(milestone, 'is_release_or_beta'))
+set_define('RELEASE_OR_BETA', delayed_getattr(milestone, 'is_release_or_beta'))
+add_old_configure_assignment('RELEASE_OR_BETA',
+                             delayed_getattr(milestone, 'is_release_or_beta'))
 
 # The app update channel is 'default' when not supplied. The value is used in
 # the application's confvars.sh (and is made available to a project specific
diff --git a/build/release/sanity.py b/build/release/sanity.py
index cd89eb3d77cf..aba8559894ba 100644
--- a/build/release/sanity.py
+++ b/build/release/sanity.py
@@ -59,7 +59,7 @@ def sendchange(branch, revision, username, master, products):
         'products:%s' % ','.join(products),
         '-p',
         'script_repo_revision:%s' % revision,
-        'release_build'
+        'release_or_beta'
     ]
     logging.info("Executing: %s" % cmd)
     run_cmd(cmd)
diff --git a/devtools/client/preferences/devtools.js b/devtools/client/preferences/devtools.js
index 9199bfd99459..6aa07a5870a9 100644
--- a/devtools/client/preferences/devtools.js
+++ b/devtools/client/preferences/devtools.js
@@ -357,7 +357,7 @@ pref("devtools.telemetry.tools.opened.version", "{}");
 
 // Enable the JSON View tool (an inspector for application/json documents) on
 // Nightly and Dev. Edition.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("devtools.jsonview.enabled", false);
 #else
 pref("devtools.jsonview.enabled", true);
diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index b61fe1f94882..19afe2d7fb89 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -1701,7 +1701,7 @@ nsWindowSH::NameStructEnabled(JSContext* aCx, nsGlobalWindow *aWin,
          OldBindingConstructorEnabled(nameStruct, aWin, aCx);
 }
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 #define USE_CONTROLLERS_SHIM
 #endif
 
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index acdd0308c4df..d618578b739f 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -860,7 +860,7 @@ nsOuterWindowProxy::defineProperty(JSContext* cx,
     return result.failCantDefineWindowElement();
   }
 
-#ifndef RELEASE_BUILD // To be turned on in bug 1178638.
+#ifndef RELEASE_OR_BETA // To be turned on in bug 1178638.
   // For now, allow chrome code to define non-configurable properties
   // on windows, until we sort out what exactly the addon SDK is
   // doing.  In the meantime, this still allows us to test web compat
diff --git a/dom/base/test/mochitest.ini b/dom/base/test/mochitest.ini
index 4004ff39e912..e30cb9a80a4f 100644
--- a/dom/base/test/mochitest.ini
+++ b/dom/base/test/mochitest.ini
@@ -825,7 +825,7 @@ skip-if = buildapp == 'b2g' || toolkit == 'android' # TC: Bug 1144079 - Re-enabl
 [test_window_constructor.html]
 [test_window_cross_origin_props.html]
 [test_window_define_nonconfigurable.html]
-skip-if = release_build
+skip-if = release_or_beta
 [test_window_define_symbol.html]
 [test_window_element_enumeration.html]
 [test_window_enumeration.html]
diff --git a/dom/canvas/test/chrome/nonchrome_webgl_debug_renderer_info.html b/dom/canvas/test/chrome/nonchrome_webgl_debug_renderer_info.html
index 1e31e2b03c68..4668f2baf375 100644
--- a/dom/canvas/test/chrome/nonchrome_webgl_debug_renderer_info.html
+++ b/dom/canvas/test/chrome/nonchrome_webgl_debug_renderer_info.html
@@ -46,12 +46,12 @@ function run(canBeUnprivileged) {
   if (canBeUnprivileged) {
     ok(exts.indexOf("WEBGL_debug_renderer_info") != -1,
        "WEBGL_debug_renderer_info should be listed by getSupportedExtensions in"
-       + " non-chrome contexts on non-RELEASE_BUILDs");
+       + " non-chrome contexts on non-RELEASE_OR_BETAs");
 
     var ext = gl.getExtension("WEBGL_debug_renderer_info");
     ok(!!ext,
        "WEBGL_debug_renderer_info should be available through getExtension in non-chrome"
-       + " contexts on non-RELEASE_BUILDs");
+       + " contexts on non-RELEASE_OR_BETAs");
 
     ok(gl.getParameter(UNMASKED_VENDOR_WEBGL) && gl.getError() == gl.NO_ERROR,
        "Should be able to query UNMASKED_VENDOR_WEBGL if enabling"
diff --git a/dom/canvas/test/chrome/test_webgl_debug_renderer_info.html b/dom/canvas/test/chrome/test_webgl_debug_renderer_info.html
index 89cfe2cf3700..9d4d38c3cdac 100644
--- a/dom/canvas/test/chrome/test_webgl_debug_renderer_info.html
+++ b/dom/canvas/test/chrome/test_webgl_debug_renderer_info.html
@@ -21,10 +21,10 @@ const UNMASKED_RENDERER_WEBGL = 0x9246;
 var Cu = parent.Components.utils;
 Cu.import("resource://gre/modules/AppConstants.jsm");
 // This gives us `AppConstants` in the global scope.
-// We need this because we only expose debug_renderer_info #ifndef MOZ_RELEASE_BUILD.
-// This should match AppConstants.RELEASE_BUILD.
+// We need this because we only expose debug_renderer_info #ifndef RELEASE_OR_BETA.
+// This should match AppConstants.RELEASE_OR_BETA.
 
-const canBeUnprivileged = !AppConstants.RELEASE_BUILD;
+const canBeUnprivileged = !AppConstants.RELEASE_OR_BETA;
 
 
 function isNonEmptyString(s)
diff --git a/dom/media/MediaPrefs.h b/dom/media/MediaPrefs.h
index 59fbf1b551e1..8e1be0478d7a 100644
--- a/dom/media/MediaPrefs.h
+++ b/dom/media/MediaPrefs.h
@@ -155,7 +155,7 @@ private:
   DECL_MEDIA_PREF("media.ogg.flac.enabled",                   FlacInOgg, bool, false);
   DECL_MEDIA_PREF("media.flac.enabled",                       FlacEnabled, bool, true);
 
-#if defined(MOZ_RUST_MP4PARSE) && !defined(RELEASE_BUILD)
+#if defined(MOZ_RUST_MP4PARSE) && !defined(RELEASE_OR_BETA)
   DECL_MEDIA_PREF("media.rust.test_mode",                     RustTestMode, bool, false);
 #endif
 
diff --git a/dom/plugins/base/nsPluginTags.cpp b/dom/plugins/base/nsPluginTags.cpp
index ab75790240a2..ddc3968fdddd 100644
--- a/dom/plugins/base/nsPluginTags.cpp
+++ b/dom/plugins/base/nsPluginTags.cpp
@@ -375,7 +375,7 @@ void nsPluginTag::InitMime(const char* const* aMimeTypes,
         break;
       case nsPluginHost::eSpecialType_None:
       default:
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
         // Allow async init for all plugins on Nightly and Aurora
         mSupportsAsyncInit = true;
 #endif
diff --git a/dom/plugins/test/mochitest/mochitest.ini b/dom/plugins/test/mochitest/mochitest.ini
index b03a39f2eab7..94a36fa8c9e2 100644
--- a/dom/plugins/test/mochitest/mochitest.ini
+++ b/dom/plugins/test/mochitest/mochitest.ini
@@ -75,7 +75,7 @@ skip-if = !crashreporter || e10s
 skip-if = !crashreporter || e10s
 [test_hidden_plugin.html]
 [test_instance_re-parent.html]
-skip-if = release_build # Bug 1172627
+skip-if = release_or_beta # Bug 1172627
 [test_instance_unparent1.html]
 [test_instance_unparent2.html]
 [test_instance_unparent3.html]
diff --git a/gfx/layers/IMFYCbCrImage.cpp b/gfx/layers/IMFYCbCrImage.cpp
index 6750e394abcd..d5943b030362 100644
--- a/gfx/layers/IMFYCbCrImage.cpp
+++ b/gfx/layers/IMFYCbCrImage.cpp
@@ -247,6 +247,10 @@ IMFYCbCrImage::GetTextureClient(KnowsCompositor* aForwarder)
     return nullptr;
   }
 
+  if (!gfx::DeviceManagerDx::Get()->CanInitializeKeyedMutexTextures()) {
+    return nullptr;
+  }
+
   if (mData.mYStride < 0 || mData.mCbCrStride < 0) {
     // D3D11 only supports unsigned stride values.
     return nullptr;
diff --git a/gfx/layers/apz/src/AndroidAPZ.cpp b/gfx/layers/apz/src/AndroidAPZ.cpp
index 2991bbca453e..70042a87033c 100644
--- a/gfx/layers/apz/src/AndroidAPZ.cpp
+++ b/gfx/layers/apz/src/AndroidAPZ.cpp
@@ -80,8 +80,9 @@ AndroidFlingAnimation::AndroidFlingAnimation(AsyncPanZoomController& aApzc,
   , mFlingDuration(0)
 {
   MOZ_ASSERT(mOverscrollHandoffChain);
-  MOZ_ASSERT(aPlatformSpecificState->AsAndroidSpecificState());
-  mOverScroller = aPlatformSpecificState->AsAndroidSpecificState()->mOverScroller;
+  AndroidSpecificState* state = aPlatformSpecificState->AsAndroidSpecificState();
+  MOZ_ASSERT(state);
+  mOverScroller = state->mOverScroller;
   MOZ_ASSERT(mOverScroller);
 
   // Drop any velocity on axes where we don't have room to scroll anyways
@@ -118,12 +119,27 @@ AndroidFlingAnimation::AndroidFlingAnimation(AsyncPanZoomController& aApzc,
 
   int32_t originX = ClampStart(mStartOffset.x, scrollRangeStartX, scrollRangeEndX);
   int32_t originY = ClampStart(mStartOffset.y, scrollRangeStartY, scrollRangeEndY);
+  if (!state->mLastFling.IsNull()) {
+    // If it's been too long since the previous fling, or if the new fling's
+    // velocity is too low, don't allow flywheel to kick in. If we do allow
+    // flywheel to kick in, then we need to update the timestamp on the
+    // StackScroller because otherwise it might use a stale velocity.
+    TimeDuration flingDuration = TimeStamp::Now() - state->mLastFling;
+    if (flingDuration.ToMilliseconds() < gfxPrefs::APZFlingAccelInterval()
+        && velocity.Length() >= gfxPrefs::APZFlingAccelMinVelocity()) {
+      bool unused = false;
+      mOverScroller->ComputeScrollOffset(flingDuration.ToMilliseconds(), &unused);
+    } else {
+      mOverScroller->ForceFinished(true);
+    }
+  }
   mOverScroller->Fling(originX, originY,
                        // Android needs the velocity in pixels per second and it is in pixels per ms.
                        (int32_t)(velocity.x * 1000.0f), (int32_t)(velocity.y * 1000.0f),
                        (int32_t)floor(scrollRangeStartX), (int32_t)ceil(scrollRangeEndX),
                        (int32_t)floor(scrollRangeStartY), (int32_t)ceil(scrollRangeEndY),
                        0, 0, 0);
+  state->mLastFling = TimeStamp::Now();
 }
 
 /**
diff --git a/gfx/layers/apz/src/AndroidAPZ.h b/gfx/layers/apz/src/AndroidAPZ.h
index d52685024926..404892da5ea6 100644
--- a/gfx/layers/apz/src/AndroidAPZ.h
+++ b/gfx/layers/apz/src/AndroidAPZ.h
@@ -23,6 +23,7 @@ public:
   }
 
   java::StackScroller::GlobalRef mOverScroller;
+  TimeStamp mLastFling;
 };
 
 class AndroidFlingAnimation: public AsyncPanZoomAnimation {
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index 0fc165a965a5..626f02a582b6 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -201,6 +201,11 @@ typedef GenericFlingAnimation FlingAnimation;
  * be disabled.\n
  * Units: milliseconds
  *
+ * \li\b apz.fling_accel_min_velocity
+ * The minimum velocity of the second fling for it to be considered for fling
+ * acceleration.
+ * Units: screen pixels per milliseconds
+ *
  * \li\b apz.fling_accel_base_mult
  * \li\b apz.fling_accel_supplemental_mult
  * When applying an acceleration on a fling, the new computed velocity is
diff --git a/gfx/layers/apz/src/GenericFlingAnimation.h b/gfx/layers/apz/src/GenericFlingAnimation.h
index 9eeb953fe8a1..deec37b47433 100644
--- a/gfx/layers/apz/src/GenericFlingAnimation.h
+++ b/gfx/layers/apz/src/GenericFlingAnimation.h
@@ -67,7 +67,8 @@ public:
     // not in APZCs further down the handoff chain during handoff.
     bool applyAcceleration = !aFlingIsHandedOff;
     if (applyAcceleration && !mApzc.mLastFlingTime.IsNull()
-        && (now - mApzc.mLastFlingTime).ToMilliseconds() < gfxPrefs::APZFlingAccelInterval()) {
+        && (now - mApzc.mLastFlingTime).ToMilliseconds() < gfxPrefs::APZFlingAccelInterval()
+        && velocity.Length() >= gfxPrefs::APZFlingAccelMinVelocity()) {
       if (SameDirection(velocity.x, mApzc.mLastFlingVelocity.x)) {
         velocity.x = Accelerate(velocity.x, mApzc.mLastFlingVelocity.x);
         FLING_LOG("%p Applying fling x-acceleration from %f to %f (delta %f)\n",
diff --git a/gfx/layers/apz/test/gtest/TestScrollHandoff.cpp b/gfx/layers/apz/test/gtest/TestScrollHandoff.cpp
index ceb75e989424..f8797c2737a6 100644
--- a/gfx/layers/apz/test/gtest/TestScrollHandoff.cpp
+++ b/gfx/layers/apz/test/gtest/TestScrollHandoff.cpp
@@ -94,6 +94,7 @@ protected:
     // whether acceleration occured.
     const float kAcceleration = 100.0f;
     SCOPED_GFX_PREF(APZFlingAccelBaseMultiplier, float, kAcceleration);
+    SCOPED_GFX_PREF(APZFlingAccelMinVelocity, float, 0.0);
 
     RefPtr<TestAsyncPanZoomController> childApzc = ApzcOf(layers[1]);
 
diff --git a/gfx/layers/client/TextureClient.cpp b/gfx/layers/client/TextureClient.cpp
index 135a85c2c3b1..62785be48c5f 100644
--- a/gfx/layers/client/TextureClient.cpp
+++ b/gfx/layers/client/TextureClient.cpp
@@ -1088,7 +1088,8 @@ TextureClient::CreateForDrawing(TextureForwarder* aAllocator,
        (!!(aAllocFlags & ALLOC_FOR_OUT_OF_BAND_CONTENT) &&
         DeviceManagerDx::Get()->GetContentDevice())) &&
       aSize.width <= aMaxTextureSize &&
-      aSize.height <= aMaxTextureSize)
+      aSize.height <= aMaxTextureSize &&
+      !(aAllocFlags & ALLOC_UPDATE_FROM_SURFACE))
   {
     data = DXGITextureData::Create(aSize, aFormat, aAllocFlags);
   }
@@ -1202,8 +1203,9 @@ TextureClient::CreateFromSurface(KnowsCompositor* aAllocator,
 
   // Fall back to using UpdateFromSurface
 
+  TextureAllocationFlags allocFlags = TextureAllocationFlags(aAllocFlags | ALLOC_UPDATE_FROM_SURFACE);
   RefPtr<TextureClient> client = CreateForDrawing(aAllocator, aSurface->GetFormat(), size,
-                                                  aSelector, aTextureFlags, aAllocFlags);
+                                                  aSelector, aTextureFlags, allocFlags);
   if (!client) {
     return nullptr;
   }
diff --git a/gfx/layers/client/TextureClient.h b/gfx/layers/client/TextureClient.h
index f8cce039a8a7..32beebfb062b 100644
--- a/gfx/layers/client/TextureClient.h
+++ b/gfx/layers/client/TextureClient.h
@@ -90,6 +90,10 @@ enum TextureAllocationFlags {
   // Disable any cross-device synchronization. This is also for TextureClientD3D11,
   // and creates a texture without KeyedMutex.
   ALLOC_MANUAL_SYNCHRONIZATION = 1 << 6,
+
+  // The texture is going to be updated using UpdateFromSurface and needs to support
+  // that call.
+  ALLOC_UPDATE_FROM_SURFACE = 1 << 7,
 };
 
 #ifdef XP_WIN
diff --git a/gfx/layers/d3d11/TextureD3D11.cpp b/gfx/layers/d3d11/TextureD3D11.cpp
index 7800e0b3fe2c..aae0707e4f95 100644
--- a/gfx/layers/d3d11/TextureD3D11.cpp
+++ b/gfx/layers/d3d11/TextureD3D11.cpp
@@ -383,6 +383,11 @@ D3D11TextureData::Create(IntSize aSize, SurfaceFormat aFormat, SourceSurface* aS
     }
   }
 
+  if (aSurface && newDesc.MiscFlags == D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX &&
+      !DeviceManagerDx::Get()->CanInitializeKeyedMutexTextures()) {
+    return nullptr;
+  }
+
   D3D11_SUBRESOURCE_DATA uploadData;
   D3D11_SUBRESOURCE_DATA* uploadDataPtr = nullptr;
   RefPtr<DataSourceSurface> srcSurf;
diff --git a/gfx/thebes/DeviceManagerDx.cpp b/gfx/thebes/DeviceManagerDx.cpp
index b2c49498ec91..03fd46731ba2 100644
--- a/gfx/thebes/DeviceManagerDx.cpp
+++ b/gfx/thebes/DeviceManagerDx.cpp
@@ -670,6 +670,18 @@ DeviceManagerDx::TextureSharingWorks()
   return mDeviceStatus->textureSharingWorks();
 }
 
+bool
+DeviceManagerDx::CanInitializeKeyedMutexTextures()
+{
+  MutexAutoLock lock(mDeviceLock);
+  if (!mDeviceStatus) {
+    return false;
+  }
+  // Disable this on all Intel devices because of crashes.
+  // See bug 1292923.
+  return mDeviceStatus->adapter().VendorId != 0x8086;
+}
+
 bool
 DeviceManagerDx::IsWARP()
 {
diff --git a/gfx/thebes/DeviceManagerDx.h b/gfx/thebes/DeviceManagerDx.h
index 013facab947b..617b098e5186 100644
--- a/gfx/thebes/DeviceManagerDx.h
+++ b/gfx/thebes/DeviceManagerDx.h
@@ -60,6 +60,13 @@ public:
   bool TextureSharingWorks();
   bool IsWARP();
 
+  // Returns true if we can create a texture with
+  // D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX and also
+  // upload texture data during the CreateTexture2D
+  // call. This crashes on some devices, so we might
+  // need to avoid it.
+  bool CanInitializeKeyedMutexTextures();
+
   bool CreateCompositorDevices();
   void CreateContentDevices();
 
diff --git a/gfx/thebes/gfxFont.cpp b/gfx/thebes/gfxFont.cpp
index d7afaf5230ff..388d6e728257 100644
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -174,7 +174,7 @@ gfxFontCache::gfxFontCache()
         obs->AddObserver(new Observer, "memory-pressure", false);
     }
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     // Currently disabled for release builds, due to unexplained crashes
     // during expiration; see bug 717175 & 894798.
     mWordCacheExpirationTimer = do_CreateInstance("@mozilla.org/timer;1");
@@ -2580,7 +2580,7 @@ gfxFont::GetShapedWord(DrawTarget *aDrawTarget,
         Telemetry::Accumulate((isContent ? Telemetry::WORD_CACHE_HITS_CONTENT :
                                    Telemetry::WORD_CACHE_HITS_CHROME),
                               aLength);
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
         if (aTextPerf) {
             aTextPerf->current.wordCacheHit++;
         }
@@ -2591,7 +2591,7 @@ gfxFont::GetShapedWord(DrawTarget *aDrawTarget,
     Telemetry::Accumulate((isContent ? Telemetry::WORD_CACHE_MISSES_CONTENT :
                                Telemetry::WORD_CACHE_MISSES_CHROME),
                           aLength);
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     if (aTextPerf) {
         aTextPerf->current.wordCacheMiss++;
     }
@@ -2855,7 +2855,7 @@ gfxFont::ShapeTextWithoutWordCache(DrawTarget *aDrawTarget,
     return ok;
 }
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 #define TEXT_PERF_INCR(tp, m) (tp ? (tp)->current.m++ : 0)
 #else
 #define TEXT_PERF_INCR(tp, m)
@@ -2895,7 +2895,7 @@ gfxFont::SplitAndInitTextRun(DrawTarget *aDrawTarget,
 
     gfxTextPerfMetrics *tp = nullptr;
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     tp = aTextRun->GetFontGroup()->GetTextPerfMetrics();
     if (tp) {
         if (mStyle.systemFont) {
diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 64663748ae3e..7b3b192a35ca 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -390,7 +390,7 @@ NS_IMPL_ISUPPORTS_INHERITED0(CrashTelemetryEvent, Runnable);
 void
 CrashStatsLogForwarder::CrashAction(LogReason aReason)
 {
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   // Non-release builds crash by default, but will use telemetry
   // if this environment variable is present.
   static bool useTelemetry = gfxEnv::GfxDevCrashTelemetry();
diff --git a/gfx/thebes/gfxPrefs.h b/gfx/thebes/gfxPrefs.h
index 421d96aec767..bd6452a9d26d 100644
--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -262,6 +262,7 @@ private:
   DECL_GFX_PREF(Live, "apz.fling_accel_base_mult",             APZFlingAccelBaseMultiplier, float, 1.0f);
   DECL_GFX_PREF(Live, "apz.fling_accel_interval_ms",           APZFlingAccelInterval, int32_t, 500);
   DECL_GFX_PREF(Live, "apz.fling_accel_supplemental_mult",     APZFlingAccelSupplementalMultiplier, float, 1.0f);
+  DECL_GFX_PREF(Live, "apz.fling_accel_min_velocity",          APZFlingAccelMinVelocity, float, 1.5f);
   DECL_GFX_PREF(Once, "apz.fling_curve_function_x1",           APZCurveFunctionX1, float, 0.0f);
   DECL_GFX_PREF(Once, "apz.fling_curve_function_x2",           APZCurveFunctionX2, float, 1.0f);
   DECL_GFX_PREF(Once, "apz.fling_curve_function_y1",           APZCurveFunctionY1, float, 0.0f);
@@ -342,7 +343,7 @@ private:
 #if defined(ANDROID)
   DECL_GFX_PREF(Once, "gfx.apitrace.enabled",                  UseApitrace, bool, false);
 #endif
-#if defined(RELEASE_BUILD)
+#if defined(RELEASE_OR_BETA)
   // "Skip" means this is locked to the default value in beta and release.
   DECL_GFX_PREF(Skip, "gfx.blocklist.all",                     BlocklistAll, int32_t, 0);
 #else
diff --git a/gfx/thebes/gfxTextRun.cpp b/gfx/thebes/gfxTextRun.cpp
index e1bf9638105f..98d0a2826478 100644
--- a/gfx/thebes/gfxTextRun.cpp
+++ b/gfx/thebes/gfxTextRun.cpp
@@ -157,7 +157,7 @@ gfxTextRun::gfxTextRun(const gfxTextRunFactory::Parameters *aParams,
     MOZ_COUNT_CTOR(gfxTextRun);
     NS_ADDREF(mFontGroup);
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     gfxTextPerfMetrics *tp = aFontGroup->GetTextPerfMetrics();
     if (tp) {
         tp->current.textrunConst++;
@@ -191,7 +191,7 @@ gfxTextRun::~gfxTextRun()
     // been told to release its reference to the group, so we mustn't do that
     // again here.
     if (!mReleasedFontGroup) {
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
         gfxTextPerfMetrics *tp = mFontGroup->GetTextPerfMetrics();
         if (tp) {
             tp->current.textrunDestr++;
@@ -2902,7 +2902,7 @@ void gfxFontGroup::ComputeRanges(nsTArray<gfxTextRange>& aRanges,
             FindFontForChar(ch, prevCh, nextCh, aRunScript, prevFont,
                             &matchType);
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
         if (MOZ_UNLIKELY(mTextPerf)) {
             if (matchType == gfxTextRange::kPrefsFallback) {
                 mTextPerf->current.fallbackPrefs++;
@@ -2961,7 +2961,7 @@ void gfxFontGroup::ComputeRanges(nsTArray<gfxTextRange>& aRanges,
 
     aRanges[lastRangeIndex].end = aLength;
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     LogModule* log = mStyle.systemFont
                    ? gfxPlatform::GetLog(eGfxLog_textrunui)
                    : gfxPlatform::GetLog(eGfxLog_textrun);
diff --git a/gfx/thebes/gfxUserFontSet.cpp b/gfx/thebes/gfxUserFontSet.cpp
index 9f28cf2e1868..717292a7ffe2 100644
--- a/gfx/thebes/gfxUserFontSet.cpp
+++ b/gfx/thebes/gfxUserFontSet.cpp
@@ -181,7 +181,7 @@ public:
     virtual ots::TableAction GetTableAction(uint32_t aTag) override {
         // Preserve Graphite, color glyph and SVG tables
         if (
-#ifdef RELEASE_BUILD // For Beta/Release, also allow OT Layout tables through
+#ifdef RELEASE_OR_BETA // For Beta/Release, also allow OT Layout tables through
                      // unchecked, and rely on harfbuzz to handle them safely.
             aTag == TRUETYPE_TAG('G', 'D', 'E', 'F') ||
             aTag == TRUETYPE_TAG('G', 'P', 'O', 'S') ||
diff --git a/ipc/chromium/src/base/pickle.h b/ipc/chromium/src/base/pickle.h
index c247c1e1ad77..d031f6124594 100644
--- a/ipc/chromium/src/base/pickle.h
+++ b/ipc/chromium/src/base/pickle.h
@@ -22,7 +22,7 @@
 #include "mozilla/ipc/Faulty.h"
 #endif
 
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
 #define MOZ_PICKLE_SENTINEL_CHECKING
 #endif
 
diff --git a/ipc/glue/BackgroundImpl.cpp b/ipc/glue/BackgroundImpl.cpp
index dae97c6993f6..16ec2c01ab21 100644
--- a/ipc/glue/BackgroundImpl.cpp
+++ b/ipc/glue/BackgroundImpl.cpp
@@ -46,7 +46,7 @@
 #include "nsXPCOMPrivate.h"
 #include "prthread.h"
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 #define THREADSAFETY_ASSERT MOZ_ASSERT
 #else
 #define THREADSAFETY_ASSERT MOZ_RELEASE_ASSERT
@@ -332,7 +332,7 @@ class ChildImpl final : public BackgroundChildImpl
   // create the background thread after application shutdown has started.
   static bool sShutdownHasStarted;
 
-#if defined(DEBUG) || !defined(RELEASE_BUILD)
+#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
   nsIThread* mBoundThread;
 #endif
 
@@ -352,7 +352,7 @@ public:
   {
     THREADSAFETY_ASSERT(mBoundThread);
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
     DebugOnly<bool> current;
 #else
     bool current;
@@ -369,7 +369,7 @@ public:
   }
 
   ChildImpl()
-#if defined(DEBUG) || !defined(RELEASE_BUILD)
+#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
   : mBoundThread(nullptr)
 #endif
 #ifdef DEBUG
@@ -450,7 +450,7 @@ private:
   {
     THREADSAFETY_ASSERT(!mBoundThread);
 
-#if defined(DEBUG) || !defined(RELEASE_BUILD)
+#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
     mBoundThread = NS_GetCurrentThread();
 #endif
 
diff --git a/js/src/builtin/TestingFunctions.cpp b/js/src/builtin/TestingFunctions.cpp
index 2597a62b13dc..02e93a411893 100644
--- a/js/src/builtin/TestingFunctions.cpp
+++ b/js/src/builtin/TestingFunctions.cpp
@@ -117,12 +117,12 @@ GetBuildConfiguration(JSContext* cx, unsigned argc, Value* vp)
     if (!JS_SetProperty(cx, info, "debug", value))
         return false;
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
     value = BooleanValue(true);
 #else
     value = BooleanValue(false);
 #endif
-    if (!JS_SetProperty(cx, info, "release", value))
+    if (!JS_SetProperty(cx, info, "release_or_beta", value))
         return false;
 
 #ifdef JS_HAS_CTYPES
diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 5693b6ed9038..6af61405d968 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -9218,7 +9218,7 @@ template <typename ParseHandler>
 bool
 Parser<ParseHandler>::warnOnceAboutExprClosure()
 {
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
     JSContext* cx = context->maybeJSContext();
     if (!cx)
         return true;
diff --git a/js/src/jit-test/tests/parser/expr-closure-warn.js b/js/src/jit-test/tests/parser/expr-closure-warn.js
index 3029a8a16ff8..faadd8eb613e 100644
--- a/js/src/jit-test/tests/parser/expr-closure-warn.js
+++ b/js/src/jit-test/tests/parser/expr-closure-warn.js
@@ -1,10 +1,10 @@
 // Expression closure should be warned once and only once.
 
-var release = getBuildConfiguration().release;
+var release_or_beta = getBuildConfiguration().release_or_beta;
 
 function testWarn(code) {
-  if (release) {
-    // Warning for expression closure is non-release-only.
+  if (release_or_beta) {
+    // Warning for expression closure is non-release-only (not Release/Beta).
     testPass(code);
     return;
   }
diff --git a/js/xpconnect/tests/chrome/test_xrayToJS.xul b/js/xpconnect/tests/chrome/test_xrayToJS.xul
index 809d8988e157..53f0100c6537 100644
--- a/js/xpconnect/tests/chrome/test_xrayToJS.xul
+++ b/js/xpconnect/tests/chrome/test_xrayToJS.xul
@@ -159,7 +159,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=933681
   // DO NOT CHANGE WTIHOUT REVIEW FROM AN XPCONNECT PEER.
   var version = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULAppInfo).version;
   var isNightlyBuild = version.endsWith("a1");
-  var isReleaseBuild = !version.includes("a");
+  var isReleaseOrBeta = !version.includes("a");
   var gPrototypeProperties = {};
   var gConstructorProperties = {};
   function constructorProps(arr) {
diff --git a/media/ffvpx/ffvpxcommon.mozbuild b/media/ffvpx/ffvpxcommon.mozbuild
index e0cccfd709ce..3a83f781d3f3 100644
--- a/media/ffvpx/ffvpxcommon.mozbuild
+++ b/media/ffvpx/ffvpxcommon.mozbuild
@@ -84,6 +84,6 @@ DEFINES['HAVE_AV_CONFIG_H'] = True
 if CONFIG['MOZ_DEBUG']:
     # Enable all assertions in debug builds.
     DEFINES['ASSERT_LEVEL'] = 2
-elif not CONFIG['RELEASE_BUILD']:
+elif not CONFIG['RELEASE_OR_BETA']:
     # Enable fast assertions in opt builds of Nightly and Aurora.
     DEFINES['ASSERT_LEVEL'] = 1
diff --git a/media/libav/moz.build b/media/libav/moz.build
index 94a92a8e9ec8..ec0de8bd048a 100644
--- a/media/libav/moz.build
+++ b/media/libav/moz.build
@@ -69,7 +69,7 @@ ALLOW_COMPILER_WARNINGS = True
 if CONFIG['MOZ_DEBUG']:
     # Enable all assertions in debug builds.
     DEFINES['ASSERT_LEVEL'] = 2
-elif not CONFIG['RELEASE_BUILD']:
+elif not CONFIG['RELEASE_OR_BETA']:
     # Enable fast assertions in opt builds of Nightly and Aurora.
     DEFINES['ASSERT_LEVEL'] = 1
 
diff --git a/media/libstagefright/binding/MP4Metadata.cpp b/media/libstagefright/binding/MP4Metadata.cpp
index 027a5fbeb13e..a50730845247 100644
--- a/media/libstagefright/binding/MP4Metadata.cpp
+++ b/media/libstagefright/binding/MP4Metadata.cpp
@@ -159,7 +159,7 @@ MP4Metadata::MP4Metadata(Stream* aSource)
  , mPreferRust(false)
  , mReportedAudioTrackTelemetry(false)
  , mReportedVideoTrackTelemetry(false)
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
  , mRustTestMode(MediaPrefs::RustTestMode())
 #endif
 #endif
@@ -280,7 +280,7 @@ MP4Metadata::GetTrackInfo(mozilla::TrackInfo::TrackType aType,
   mozilla::UniquePtr<mozilla::TrackInfo> infoRust =
       mRust->GetTrackInfo(aType, aTrackNumber);
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   if (mRustTestMode && info) {
     MOZ_DIAGNOSTIC_ASSERT(infoRust);
     MOZ_DIAGNOSTIC_ASSERT(infoRust->mId == info->mId);
diff --git a/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h b/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
index 9a43dd352684..83eca69d33c4 100644
--- a/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
+++ b/media/libstagefright/binding/include/mp4_demuxer/MP4Metadata.h
@@ -42,7 +42,7 @@ private:
   mutable bool mPreferRust;
   mutable bool mReportedAudioTrackTelemetry;
   mutable bool mReportedVideoTrackTelemetry;
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   mutable bool mRustTestMode;
 #endif
   bool ShouldPreferRust() const;
diff --git a/mfbt/Assertions.h b/mfbt/Assertions.h
index 4361c253a649..cf2b5232572d 100644
--- a/mfbt/Assertions.h
+++ b/mfbt/Assertions.h
@@ -398,7 +398,7 @@ struct AssertionConditionType
 #  define MOZ_ASSERT(...) do { } while (0)
 #endif /* DEBUG */
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 #  define MOZ_DIAGNOSTIC_ASSERT MOZ_ASSERT
 #else
 #  define MOZ_DIAGNOSTIC_ASSERT MOZ_RELEASE_ASSERT
diff --git a/mobile/android/app/mobile.js b/mobile/android/app/mobile.js
index 256bbc8537ee..8cad5465ec61 100644
--- a/mobile/android/app/mobile.js
+++ b/mobile/android/app/mobile.js
@@ -300,7 +300,7 @@ pref("browser.search.noCurrentEngine", true);
 
 // Control media casting & mirroring features
 pref("browser.casting.enabled", true);
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 // Chromecast mirroring is broken (bug 1131084)
 pref("browser.mirroring.enabled", false);
 #else
@@ -863,13 +863,13 @@ pref("layout.accessiblecaret.hapticfeedback", true);
 pref("layout.accessiblecaret.extend_selection_for_phone_number", true);
 
 // Disable sending console to logcat on release builds.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("consoleservice.logcat", false);
 #else
 pref("consoleservice.logcat", true);
 #endif
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 // Enable VR on mobile, making it enable by default.
 pref("dom.vr.enabled", true);
 #endif
diff --git a/mobile/android/base/AppConstants.java.in b/mobile/android/base/AppConstants.java.in
index 6fd2532fd661..fa50440d5fe7 100644
--- a/mobile/android/base/AppConstants.java.in
+++ b/mobile/android/base/AppConstants.java.in
@@ -240,8 +240,8 @@ public class AppConstants {
 
     // See this wiki page for more details about channel specific build defines:
     // https://wiki.mozilla.org/Platform/Channel-specific_build_defines
-    public static final boolean RELEASE_BUILD =
-//#ifdef RELEASE_BUILD
+    public static final boolean RELEASE_OR_BETA =
+//#ifdef RELEASE_OR_BETA
     true;
 //#else
     false;
diff --git a/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java b/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java
index b025b3529b1a..1f3d6bbb327f 100644
--- a/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java
+++ b/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java
@@ -804,10 +804,10 @@ public class BrowserApp extends GeckoApp
         // Set the maximum bits-per-pixel the favicon system cares about.
         IconDirectoryEntry.setMaxBPP(GeckoAppShell.getScreenDepth());
 
-        // The update service is enabled for RELEASE_BUILD, which includes the release and beta channels.
+        // The update service is enabled for RELEASE_OR_BETA, which includes the release and beta channels.
         // However, no updates are served.  Therefore, we don't trust the update service directly, and
         // try to avoid prompting unnecessarily. See Bug 1232798.
-        if (!AppConstants.RELEASE_BUILD && UpdateServiceHelper.isUpdaterEnabled(this)) {
+        if (!AppConstants.RELEASE_OR_BETA && UpdateServiceHelper.isUpdaterEnabled(this)) {
             Permissions.from(this)
                        .withPermissions(Manifest.permission.WRITE_EXTERNAL_STORAGE)
                        .doNotPrompt()
@@ -4171,7 +4171,7 @@ public class BrowserApp extends GeckoApp
      * @return true if update UI was launched.
      */
     protected boolean handleUpdaterLaunch() {
-        if (AppConstants.RELEASE_BUILD) {
+        if (AppConstants.RELEASE_OR_BETA) {
             Intent intent = new Intent(Intent.ACTION_VIEW);
             intent.setData(Uri.parse("market://details?id=" + getPackageName()));
             startActivity(intent);
diff --git a/mobile/android/base/java/org/mozilla/gecko/Telemetry.java b/mobile/android/base/java/org/mozilla/gecko/Telemetry.java
index 306cdd0cb97a..342445bf21c9 100644
--- a/mobile/android/base/java/org/mozilla/gecko/Telemetry.java
+++ b/mobile/android/base/java/org/mozilla/gecko/Telemetry.java
@@ -196,7 +196,7 @@ public class Telemetry {
             throw new IllegalArgumentException("Expected non-null method - use Method.NONE?");
         }
 
-        if (!AppConstants.RELEASE_BUILD) {
+        if (!AppConstants.RELEASE_OR_BETA) {
             final String logString = "SendUIEvent: event = " + eventName + " method = " + method + " timestamp = " +
                     timestamp + " extras = " + extras;
             Log.d(LOGTAG, logString);
diff --git a/mobile/android/base/java/org/mozilla/gecko/menu/GeckoMenu.java b/mobile/android/base/java/org/mozilla/gecko/menu/GeckoMenu.java
index b7b1102f552f..512f320025d7 100644
--- a/mobile/android/base/java/org/mozilla/gecko/menu/GeckoMenu.java
+++ b/mobile/android/base/java/org/mozilla/gecko/menu/GeckoMenu.java
@@ -44,7 +44,7 @@ public class GeckoMenu extends ListView
      * Controls whether off-UI-thread method calls in this class cause an
      * exception or just logging.
      */
-    private static final AssertBehavior THREAD_ASSERT_BEHAVIOR = AppConstants.RELEASE_BUILD ? AssertBehavior.NONE : AssertBehavior.THROW;
+    private static final AssertBehavior THREAD_ASSERT_BEHAVIOR = AppConstants.RELEASE_OR_BETA ? AssertBehavior.NONE : AssertBehavior.THROW;
 
     /*
      * A callback for a menu item click/long click event.
diff --git a/mobile/android/base/java/org/mozilla/gecko/updater/UpdateService.java b/mobile/android/base/java/org/mozilla/gecko/updater/UpdateService.java
index 018a59c67e77..21f33fc26afd 100644
--- a/mobile/android/base/java/org/mozilla/gecko/updater/UpdateService.java
+++ b/mobile/android/base/java/org/mozilla/gecko/updater/UpdateService.java
@@ -226,7 +226,7 @@ public class UpdateService extends IntentService {
         int interval;
         if (isRetry) {
             interval = INTERVAL_RETRY;
-        } else if (!AppConstants.RELEASE_BUILD) {
+        } else if (!AppConstants.RELEASE_OR_BETA) {
             interval = INTERVAL_SHORT;
         } else {
             interval = INTERVAL_LONG;
diff --git a/mobile/android/chrome/content/about.xhtml b/mobile/android/chrome/content/about.xhtml
index 0a490f506705..8a4c283571c6 100644
--- a/mobile/android/chrome/content/about.xhtml
+++ b/mobile/android/chrome/content/about.xhtml
@@ -65,7 +65,7 @@
       <div class="bottom-border"></div>
     </ul>
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
     <div id="aboutDetails">
       <p>&aboutPage.logoTrademark;</p>
     </div>
diff --git a/mobile/android/chrome/content/browser.js b/mobile/android/chrome/content/browser.js
index 9465ec5a78b5..b31cba1b9b52 100644
--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -133,7 +133,7 @@ var lazilyLoadedBrowserScripts = [
   ["CastingApps", "chrome://browser/content/CastingApps.js"],
   ["RemoteDebugger", "chrome://browser/content/RemoteDebugger.js"],
 ];
-if (!AppConstants.RELEASE_BUILD) {
+if (!AppConstants.RELEASE_OR_BETA) {
   lazilyLoadedBrowserScripts.push(
     ["WebcompatReporter", "chrome://browser/content/WebcompatReporter.js"]);
 }
@@ -520,7 +520,7 @@ var BrowserApp = {
       InitLater(() => Services.obs.notifyObservers(window, "browser-delayed-startup-finished", ""));
       InitLater(() => Messaging.sendRequest({ type: "Gecko:DelayedStartup" }));
 
-      if (!AppConstants.RELEASE_BUILD) {
+      if (!AppConstants.RELEASE_OR_BETA) {
         InitLater(() => WebcompatReporter.init());
       }
 
diff --git a/mobile/android/chrome/jar.mn b/mobile/android/chrome/jar.mn
index fd5074d53f42..199a4511bab6 100644
--- a/mobile/android/chrome/jar.mn
+++ b/mobile/android/chrome/jar.mn
@@ -59,7 +59,7 @@ chrome.jar:
   content/aboutAccounts.js             (content/aboutAccounts.js)
   content/aboutLogins.xhtml            (content/aboutLogins.xhtml)
   content/aboutLogins.js               (content/aboutLogins.js)
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   content/WebcompatReporter.js         (content/WebcompatReporter.js)
 #endif
 
diff --git a/mobile/android/components/MobileComponents.manifest b/mobile/android/components/MobileComponents.manifest
index 462fc70a1654..ed38b9fa8587 100644
--- a/mobile/android/components/MobileComponents.manifest
+++ b/mobile/android/components/MobileComponents.manifest
@@ -99,7 +99,7 @@ component {d1bbb0fd-1d47-4134-9c12-d7b1be20b721} FxAccountsPush.js
 contract @mozilla.org/fxa-push;1 {d1bbb0fd-1d47-4134-9c12-d7b1be20b721}
 category android-push-service FxAccountsPush @mozilla.org/fxa-push;1
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 # TabSource.js
 component {5850c76e-b916-4218-b99a-31f004e0a7e7} TabSource.js
 contract @mozilla.org/tab-source-service;1 {5850c76e-b916-4218-b99a-31f004e0a7e7}
diff --git a/mobile/android/confvars.sh b/mobile/android/confvars.sh
index 448f074cd70e..f4f83768adfc 100644
--- a/mobile/android/confvars.sh
+++ b/mobile/android/confvars.sh
@@ -42,7 +42,7 @@ MOZ_NATIVE_DEVICES=1
 
 # Enable install tracking SDK if we have Google Play support; MOZ_NATIVE_DEVICES
 # is a proxy flag for that support.
-if test "$RELEASE_BUILD"; then
+if test "$RELEASE_OR_BETA"; then
 if test "$MOZ_NATIVE_DEVICES"; then
   MOZ_INSTALL_TRACKING=1
 fi
diff --git a/mobile/android/docs/adjust.rst b/mobile/android/docs/adjust.rst
index a37e172c5d58..16cb85b2bb24 100644
--- a/mobile/android/docs/adjust.rst
+++ b/mobile/android/docs/adjust.rst
@@ -127,10 +127,10 @@ Add the following to your mozconfig to compile with the Adjust SDK::
 
  export MOZ_INSTALL_TRACKING=1
  export MOZ_NATIVE_DEVICES=1
- export RELEASE_BUILD=1
+ export RELEASE_OR_BETA=1
  ac_add_options --with-adjust-sdk-keyfile="$topsrcdir/mobile/android/base/adjust-sdk-sandbox.token"
 
-``MOZ_NATIVE_DEVICES`` && ``RELEASE_BUILD`` are required for an unknown
+``MOZ_NATIVE_DEVICES`` && ``RELEASE_OR_BETA`` are required for an unknown
 reason.  If you build without them, the ``StubAdjustHelper`` will be
 returned.
 
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java
index 61a72f83880a..6c4e67b433a0 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java
@@ -81,7 +81,7 @@ public final class EventDispatcher {
                         listeners = type.newInstance();
                         listenersMap.put(event, listeners);
                     }
-                    if (!AppConstants.RELEASE_BUILD && listeners.contains(listener)) {
+                    if (!AppConstants.RELEASE_OR_BETA && listeners.contains(listener)) {
                         throw new IllegalStateException("Already registered " + event);
                     }
                     listeners.add(listener);
@@ -94,7 +94,7 @@ public final class EventDispatcher {
 
     private void checkNotRegisteredElsewhere(final Map<String, ?> allowedMap,
                                              final String[] events) {
-        if (AppConstants.RELEASE_BUILD) {
+        if (AppConstants.RELEASE_OR_BETA) {
             // for performance reasons, we only check for
             // already-registered listeners in non-release builds.
             return;
@@ -124,7 +124,7 @@ public final class EventDispatcher {
             for (final String event : events) {
                 List<T> listeners = listenersMap.get(event);
                 if ((listeners == null ||
-                     !listeners.remove(listener)) && !AppConstants.RELEASE_BUILD) {
+                     !listeners.remove(listener)) && !AppConstants.RELEASE_OR_BETA) {
                     throw new IllegalArgumentException(event + " was not registered");
                 }
             }
@@ -333,7 +333,7 @@ public final class EventDispatcher {
             Log.w(LOGTAG, "No listeners for " + type + " in dispatchToThreads");
         }
 
-        if (!AppConstants.RELEASE_BUILD && jsMessage == null) {
+        if (!AppConstants.RELEASE_OR_BETA && jsMessage == null) {
             // We're dispatching a Bundle message. Because Gecko thread listeners are not
             // supported for Bundle messages, do a sanity check to make sure we don't have
             // matching Gecko thread listeners.
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java
index 07f2b4915976..27ec4f1dd6af 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java
@@ -52,7 +52,7 @@ public final class GeckoProfile {
     private static final String PROFILE_CREATION_DATE_JSON_ATTR = "created";
 
     // Only tests should need to do this.
-    // We can default this to AppConstants.RELEASE_BUILD once we fix Bug 1069687.
+    // We can default this to AppConstants.RELEASE_OR_BETA once we fix Bug 1069687.
     private static volatile boolean sAcceptDirectoryChanges = true;
 
     @RobocopTarget
@@ -268,7 +268,7 @@ public final class GeckoProfile {
                             "Refusing to reuse profile with a different directory.");
                 }
 
-                if (AppConstants.RELEASE_BUILD) {
+                if (AppConstants.RELEASE_OR_BETA) {
                     Log.e(LOGTAG, "Release build trying to switch out profile dir. " +
                                   "This is an error, but let's do what we can.");
                 }
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/StackScroller.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/StackScroller.java
index aae8235bc614..293268cba14f 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/StackScroller.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/StackScroller.java
@@ -261,9 +261,14 @@ public class StackScroller {
         if (mFlywheel && !isFinished()) {
             float oldVelocityX = mScrollerX.mCurrVelocity;
             float oldVelocityY = mScrollerY.mCurrVelocity;
-            if (Math.signum(velocityX) == Math.signum(oldVelocityX)
-                    && Math.signum(velocityY) == Math.signum(oldVelocityY)) {
+            boolean sameXDirection = (velocityX == 0) || (oldVelocityX == 0) ||
+                ((velocityX < 0) == (oldVelocityX < 0));
+            boolean sameYDirection = (velocityY == 0) || (oldVelocityY == 0) ||
+                ((velocityY < 0) == (oldVelocityY < 0));
+            if (sameXDirection) {
                 velocityX += oldVelocityX;
+            }
+            if (sameYDirection) {
                 velocityY += oldVelocityY;
             }
         }
diff --git a/mobile/android/installer/package-manifest.in b/mobile/android/installer/package-manifest.in
index 282ea000e6e1..186b51b674cb 100644
--- a/mobile/android/installer/package-manifest.in
+++ b/mobile/android/installer/package-manifest.in
@@ -317,7 +317,7 @@
 @BINPATH@/components/amWebAPI.js
 @BINPATH@/components/amWebInstallListener.js
 @BINPATH@/components/nsBlocklistService.js
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 @BINPATH@/components/TabSource.js
 #endif
 @BINPATH@/components/webvtt.xpt
diff --git a/mobile/android/locales/jar.mn b/mobile/android/locales/jar.mn
index a2146319a7ac..011e409c2cb2 100644
--- a/mobile/android/locales/jar.mn
+++ b/mobile/android/locales/jar.mn
@@ -31,7 +31,7 @@
   locale/@AB_CD@/browser/handling.properties      (%chrome/handling.properties)
   locale/@AB_CD@/browser/aboutLogins.dtd          (%chrome/aboutLogins.dtd)
   locale/@AB_CD@/browser/aboutLogins.properties  (%chrome/aboutLogins.properties)
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   locale/@AB_CD@/browser/webcompatReporter.properties (%chrome/webcompatReporter.properties)
 #endif
 % resource search-plugins chrome://browser/locale/searchplugins/
diff --git a/mobile/android/tests/browser/junit3/src/org/mozilla/tests/browser/junit3/TestGeckoMenu.java b/mobile/android/tests/browser/junit3/src/org/mozilla/tests/browser/junit3/TestGeckoMenu.java
index c8374401d907..15be26004107 100644
--- a/mobile/android/tests/browser/junit3/src/org/mozilla/tests/browser/junit3/TestGeckoMenu.java
+++ b/mobile/android/tests/browser/junit3/src/org/mozilla/tests/browser/junit3/TestGeckoMenu.java
@@ -60,7 +60,7 @@ public class TestGeckoMenu extends InstrumentationTestCase {
             semaphore.wait();
         }
 
-        if (AppConstants.RELEASE_BUILD) {
+        if (AppConstants.RELEASE_OR_BETA) {
             // No exception thrown: release build.
             assertNull(exception);
             return;
diff --git a/mobile/android/tests/browser/robocop/src/org/mozilla/gecko/tests/testGetUserMedia.java b/mobile/android/tests/browser/robocop/src/org/mozilla/gecko/tests/testGetUserMedia.java
index 5bbf366ef1b4..405ddef7a8a6 100644
--- a/mobile/android/tests/browser/robocop/src/org/mozilla/gecko/tests/testGetUserMedia.java
+++ b/mobile/android/tests/browser/robocop/src/org/mozilla/gecko/tests/testGetUserMedia.java
@@ -32,7 +32,7 @@ public class testGetUserMedia extends BaseTest {
 
     public void testGetUserMedia() {
         // TabShare.js is disabled on release builds.
-        if (AppConstants.RELEASE_BUILD) {
+        if (AppConstants.RELEASE_OR_BETA) {
             mAsserter.dumpLog(LOGTAG + " is disabled on release builds: returning");
             return;
         }
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 48758e31f111..4f4404b03cc2 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -188,7 +188,7 @@ pref("dom.enable_performance_observer", false);
 // Whether the Gamepad API is enabled
 pref("dom.gamepad.enabled", true);
 pref("dom.gamepad.test.enabled", false);
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.gamepad.non_standard_events.enabled", false);
 #else
 pref("dom.gamepad.non_standard_events.enabled", true);
@@ -298,7 +298,7 @@ pref("mathml.disabled",    false);
 pref("mathml.scale_stretchy_operators.enabled", true);
 
 // Disable MediaError.message.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.MediaError.message.enabled", false);
 #else
 pref("dom.MediaError.message.enabled", true);
@@ -537,7 +537,7 @@ pref("dom.webaudio.enabled", true);
 pref("media.getusermedia.screensharing.enabled", true);
 #endif
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("media.getusermedia.screensharing.allowed_domains", "webex.com,*.webex.com,ciscospark.com,*.ciscospark.com,projectsquared.com,*.projectsquared.com,*.room.co,room.co,beta.talky.io,talky.io,*.clearslide.com,appear.in,*.appear.in,tokbox.com,*.tokbox.com,*.sso.francetelecom.fr,*.si.francetelecom.fr,*.sso.infra.ftgroup,*.multimedia-conference.orange-business.com,*.espacecollaboration.orange-business.com,free.gotomeeting.com,g2m.me,*.g2m.me,*.mypurecloud.com,*.mypurecloud.com.au,spreed.me,*.spreed.me,*.spreed.com,air.mozilla.org,*.circuit.com,*.yourcircuit.com,circuit.siemens.com,yourcircuit.siemens.com,circuitsandbox.net,*.unify.com,tandi.circuitsandbox.net,*.ericsson.net,*.cct.ericsson.net,*.opentok.com,*.conf.meetecho.com,meet.jit.si,*.meet.jit.si,web.stage.speakeasyapp.net,web.speakeasyapp.net,*.hipchat.me,*.beta-wspbx.com,*.wspbx.com,*.unifiedcloudit.com,*.smartboxuc.com,*.smartbox-uc.com,*.panterranetworks.com,pexipdemo.com,*.pexipdemo.com,pex.me,*.pex.me,*.rd.pexip.com,1click.io,*.1click.io,*.fuze.com,*.fuzemeeting.com,*.thinkingphones.com,gotomeeting.com,*.gotomeeting.com,gotowebinar.com,*.gotowebinar.com,gototraining.com,*.gototraining.com,citrix.com,*.citrix.com,expertcity.com,*.expertcity.com,citrixonline.com,*.citrixonline.com,g2m.me,*.g2m.me,gotomeet.me,*.gotomeet.me,gotomeet.at,*.gotomeet.at,miriadaxdes.miriadax.net,certificacion.miriadax.net,miriadax.net,*.wire.com,sylaps.com,*.sylaps.com,bluejeans.com,*.bluejeans.com,*.a.bluejeans.com");
 #else
  // includes Mozilla's test domain: mozilla.github.io (not intended for release)
@@ -633,6 +633,7 @@ pref("apz.displayport_expiry_ms", 15000);
 pref("apz.enlarge_displayport_when_clipped", false);
 pref("apz.fling_accel_base_mult", "1.0");
 pref("apz.fling_accel_interval_ms", 500);
+pref("apz.fling_accel_min_velocity", "1.5");
 pref("apz.fling_accel_supplemental_mult", "1.0");
 pref("apz.fling_curve_function_x1", "0.0");
 pref("apz.fling_curve_function_y1", "0.0");
@@ -838,7 +839,7 @@ pref("canvas.path.enabled", true);
 pref("canvas.capturestream.enabled", true);
 
 // Disable the ImageBitmap-extensions in the release build.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("canvas.imagebitmap_extensions.enabled", false);
 #else
 pref("canvas.imagebitmap_extensions.enabled", true);
@@ -1218,7 +1219,7 @@ pref("privacy.trackingprotection.pbmode.enabled",  true);
 
 pref("dom.event.contextmenu.enabled",       true);
 pref("dom.event.clipboardevents.enabled",   true);
-#if defined(XP_WIN) && !defined(RELEASE_BUILD) || defined(MOZ_WIDGET_GTK) && !defined(RELEASE_BUILD)
+#if defined(XP_WIN) && !defined(RELEASE_OR_BETA) || defined(MOZ_WIDGET_GTK) && !defined(RELEASE_OR_BETA)
 pref("dom.event.highrestimestamp.enabled",  true);
 #else
 pref("dom.event.highrestimestamp.enabled",  false);
@@ -1239,7 +1240,7 @@ pref("javascript.options.wasm",             false);
 pref("javascript.options.wasm_baselinejit", false);
 pref("javascript.options.native_regexp",    true);
 pref("javascript.options.parallel_parsing", true);
-#if !defined(RELEASE_BUILD) && !defined(ANDROID) && !defined(MOZ_B2G) && !defined(XP_IOS)
+#if !defined(RELEASE_OR_BETA) && !defined(ANDROID) && !defined(MOZ_B2G) && !defined(XP_IOS)
 pref("javascript.options.asyncstack",       true);
 #else
 pref("javascript.options.asyncstack",       false);
@@ -1538,7 +1539,7 @@ pref("network.http.fast-fallback-to-IPv4", true);
 
 // The maximum amount of time the cache session lock can be held
 // before a new transaction bypasses the cache. In milliseconds.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("network.http.bypass-cachelock-threshold", 200000);
 #else
 pref("network.http.bypass-cachelock-threshold", 250);
@@ -1668,7 +1669,7 @@ pref("dom.server-events.default-reconnection-time", 5000); // in milliseconds
 // by the jar channel.
 pref("network.jar.open-unsafe-types", false);
 // If true, loading remote JAR files using the jar: protocol will be prevented.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 // Keep allowing remote JAR files for IBM iNotes (see bug 1255139) for now.
 pref("network.jar.block-remote-files", false);
 #else
@@ -2506,14 +2507,14 @@ pref("layout.css.DOMQuad.enabled", true);
 pref("layout.css.DOMMatrix.enabled", true);
 
 // Is support for GeometryUtils.getBoxQuads enabled?
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("layout.css.getBoxQuads.enabled", false);
 #else
 pref("layout.css.getBoxQuads.enabled", true);
 #endif
 
 // Is support for GeometryUtils.convert*FromNode enabled?
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("layout.css.convertFromNode.enabled", false);
 #else
 pref("layout.css.convertFromNode.enabled", true);
@@ -2524,7 +2525,7 @@ pref("layout.css.text-align-unsafe-value.enabled", false);
 
 // Is support for CSS "float: inline-{start,end}" and
 // "clear: inline-{start,end}" enabled?
-#if defined(MOZ_B2G) || !defined(RELEASE_BUILD)
+#if defined(MOZ_B2G) || !defined(RELEASE_OR_BETA)
 pref("layout.css.float-logical-values.enabled", true);
 #else
 pref("layout.css.float-logical-values.enabled", false);
@@ -2601,7 +2602,7 @@ pref("layout.css.variables.enabled", true);
 pref("layout.css.overflow-clip-box.enabled", false);
 
 // Is support for CSS grid enabled?
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("layout.css.grid.enabled", false);
 #else
 pref("layout.css.grid.enabled", true);
@@ -2654,7 +2655,7 @@ pref("layout.css.shape-outside.enabled", false);
 pref("layout.css.font-loading-api.enabled", true);
 
 // Should stray control characters be rendered visibly?
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("layout.css.control-characters.visible", false);
 #else
 pref("layout.css.control-characters.visible", true);
@@ -2706,7 +2707,7 @@ pref("layout.float-fragments-inside-column.enabled", true);
 // Before enabling this by default, make sure also CSSPseudoElement interface
 // has been spec'ed properly, or we should add a separate pref for
 // CSSPseudoElement interface. See Bug 1174575 for further details.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.animations-api.core.enabled", false);
 #else
 pref("dom.animations-api.core.enabled", true);
@@ -2854,11 +2855,11 @@ pref("svg.marker-improvements.enabled", true);
 // See https://svgwg.org/svg2-draft/single-page.html#types-SVGBoundingBoxOptions
 pref("svg.new-getBBox.enabled", false);
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("svg.transform-box.enabled", false);
 #else
 pref("svg.transform-box.enabled", true);
-#endif // RELEASE_BUILD
+#endif // RELEASE_OR_BETA
 
 // Default font types and sizes by locale
 pref("font.default.ar", "sans-serif");
@@ -4462,7 +4463,7 @@ pref("webgl.webgl2-compat-mode", false);
 
 pref("webgl.enable-webgl2", true);
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 // Keep this disabled on Release and Beta for now. (see bug 1171228)
 pref("webgl.enable-debug-renderer-info", false);
 #else
@@ -4697,7 +4698,7 @@ pref("alerts.showFavicons", false);
 
 // DOM full-screen API.
 pref("full-screen-api.enabled", false);
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("full-screen-api.unprefix.enabled", false);
 #else
 pref("full-screen-api.unprefix.enabled", true);
@@ -4950,7 +4951,7 @@ pref("dom.browserElement.maxScreenshotDelayMS", 2000);
 pref("dom.placeholder.show_on_focus", true);
 
 // VR is disabled by default in release and enabled for nightly and aurora
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.vr.enabled", false);
 #else
 pref("dom.vr.enabled", true);
@@ -5037,7 +5038,7 @@ pref("captivedetect.maxWaitingTime", 5000);
 pref("captivedetect.pollingTime", 3000);
 pref("captivedetect.maxRetryCount", 5);
 
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.forms.inputmode", false);
 #else
 pref("dom.forms.inputmode", true);
@@ -5302,7 +5303,7 @@ pref("dom.presentation.discoverable.retry_ms", 5000);
 pref("dom.presentation.session_transport.data_channel.enable", false);
 
 #ifdef XP_MACOSX
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
 // In non-release builds we crash by default on insecure text input (when a
 // password editor has focus but secure event input isn't enabled).  The
 // following pref, when turned on, disables this behavior.  See bug 1188425.
@@ -5513,7 +5514,7 @@ pref("layout.css.color-adjust.enabled", true);
 pref("dom.audiochannel.audioCompeting", false);
 
 // Disable Node.rootNode in release builds.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("dom.node.rootNode.enabled", false);
 #else
 pref("dom.node.rootNode.enabled", true);
@@ -5524,7 +5525,7 @@ pref("media.default_volume", "1.0");
 
 // Once bug 1276272 is resolved, we will trun this preference to default ON in
 // non-release channels.
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("media.seekToNextFrame.enabled", false);
 #else
 pref("media.seekToNextFrame.enabled", true);
@@ -5534,7 +5535,7 @@ pref("media.seekToNextFrame.enabled", true);
 pref("dom.maxHardwareConcurrency", 16);
 
 // Shutdown the osfile worker if its no longer needed.
-#if !defined(RELEASE_BUILD)
+#if !defined(RELEASE_OR_BETA)
 pref("osfile.reset_worker_delay", 30000);
 #endif
 
@@ -5553,7 +5554,7 @@ pref("layout.css.servo.enabled", true);
 // If a request is mixed-content, send an HSTS priming request to attempt to
 // see if it is available over HTTPS.
 pref("security.mixed_content.send_hsts_priming", true);
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 // Don't change the order of evaluation of mixed-content and HSTS upgrades in
 // order to be most compatible with current standards
 pref("security.mixed_content.use_hsts", false);
diff --git a/moz.configure b/moz.configure
index 3b9269b10011..4802e5ed4996 100644
--- a/moz.configure
+++ b/moz.configure
@@ -18,7 +18,7 @@ include('build/moz.configure/init.configure')
 # To be removed in Bug 1003313
 @depends(milestone)
 def e10s_testing_only(milestone):
-    if not milestone.is_release:
+    if not milestone.is_release_or_beta:
         return True
 
 set_config('E10S_TESTING_ONLY', e10s_testing_only)
diff --git a/mozglue/android/APKOpen.cpp b/mozglue/android/APKOpen.cpp
index 1b5dc987bb65..9a70cf1251af 100644
--- a/mozglue/android/APKOpen.cpp
+++ b/mozglue/android/APKOpen.cpp
@@ -42,7 +42,7 @@
 #define RUSAGE_THREAD 1
 #endif
 
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
 /* Official builds have the debuggable flag set to false, which disables
  * the backtrace dumper from bionic. However, as it is useful for native
  * crashes happening before the crash reporter is registered, re-enable
diff --git a/netwerk/base/security-prefs.js b/netwerk/base/security-prefs.js
index c4696a0057a8..b0c9916c87f5 100644
--- a/netwerk/base/security-prefs.js
+++ b/netwerk/base/security-prefs.js
@@ -68,7 +68,7 @@ pref("security.pki.sha1_enforcement_level", 4);
 // 2: fall back to the subject common name for certificates valid before 23
 //    August 2015 if necessary
 // 3: only use name information from the subject alternative name extension
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("security.pki.name_matching_mode", 1);
 #else
 pref("security.pki.name_matching_mode", 2);
@@ -80,7 +80,7 @@ pref("security.pki.name_matching_mode", 2);
 // 1: it is considered equivalent when the notBefore is before 23 August 2016
 // 2: similarly, but for 23 August 2015
 // 3: it is never considered equivalent
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 pref("security.pki.netscape_step_up_policy", 1);
 #else
 pref("security.pki.netscape_step_up_policy", 2);
@@ -107,7 +107,7 @@ pref("security.cert_pinning.max_max_age_seconds", 5184000);
 // If a request is mixed-content, send an HSTS priming request to attempt to
 // see if it is available over HTTPS.
 pref("security.mixed_content.send_hsts_priming", true);
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
 // Don't change the order of evaluation of mixed-content and HSTS upgrades
 pref("security.mixed_content.use_hsts", false);
 #else
diff --git a/netwerk/ipc/NeckoParent.cpp b/netwerk/ipc/NeckoParent.cpp
index 4998dfbafdb5..5553378d3498 100644
--- a/netwerk/ipc/NeckoParent.cpp
+++ b/netwerk/ipc/NeckoParent.cpp
@@ -110,7 +110,7 @@ PBOverrideStatusFromLoadContext(const SerializedLoadContext& aSerialized)
 static MOZ_NORETURN MOZ_COLD
 void CrashWithReason(const char * reason)
 {
-#ifndef RELEASE_BUILD
+#ifndef RELEASE_OR_BETA
   MOZ_CRASH_ANNOTATE(reason);
   MOZ_REALLY_CRASH();
 #endif
diff --git a/old-configure.in b/old-configure.in
index c25d1372c1b8..85c2fbbddbe2 100644
--- a/old-configure.in
+++ b/old-configure.in
@@ -5700,7 +5700,7 @@ if test "$MOZ_TELEMETRY_REPORTING"; then
     AC_DEFINE(MOZ_TELEMETRY_REPORTING)
 
     # Enable Telemetry by default for nightly and aurora channels
-    if test -z "$RELEASE_BUILD"; then
+    if test -z "$RELEASE_OR_BETA"; then
       AC_DEFINE(MOZ_TELEMETRY_ON_BY_DEFAULT)
     fi
 fi
@@ -5998,7 +5998,7 @@ dnl ========================================================
 # Refer to bug 1281101 for more details.
 
 # Enable mask-as-shorthand property by default for nightly and aurora channels
-if test -z "$RELEASE_BUILD"; then
+if test -z "$RELEASE_OR_BETA"; then
   dnl mask as shorthand property enabled
   MOZ_ENABLE_MASK_AS_SHORTHAND=1
   AC_DEFINE(MOZ_ENABLE_MASK_AS_SHORTHAND)
diff --git a/python/mozbuild/mozbuild/mozinfo.py b/python/mozbuild/mozbuild/mozinfo.py
index 35a3a7c00728..f0b0df9bb0af 100755
--- a/python/mozbuild/mozbuild/mozinfo.py
+++ b/python/mozbuild/mozbuild/mozinfo.py
@@ -80,7 +80,7 @@ def build_dict(config, env=os.environ):
 
     d['debug'] = substs.get('MOZ_DEBUG') == '1'
     d['nightly_build'] = substs.get('NIGHTLY_BUILD') == '1'
-    d['release_build'] = substs.get('RELEASE_BUILD') == '1'
+    d['release_or_beta'] = substs.get('RELEASE_OR_BETA') == '1'
     d['pgo'] = substs.get('MOZ_PGO') == '1'
     d['crashreporter'] = bool(substs.get('MOZ_CRASHREPORTER'))
     d['datareporting'] = bool(substs.get('MOZ_DATA_REPORTING'))
diff --git a/testing/mozharness/configs/single_locale/release_mozilla-beta_android_api_15.py b/testing/mozharness/configs/single_locale/release_mozilla-beta_android_api_15.py
index e2e9c9c34218..976f21f44407 100644
--- a/testing/mozharness/configs/single_locale/release_mozilla-beta_android_api_15.py
+++ b/testing/mozharness/configs/single_locale/release_mozilla-beta_android_api_15.py
@@ -19,7 +19,7 @@ config = {
     "ignore_locales": ["en-US"],
     "balrog_credentials_file": "oauth.txt",
     "tools_repo": "https://hg.mozilla.org/build/tools",
-    "is_release": True,
+    "is_release_or_beta": True,
     "tooltool_config": {
         "manifest": "mobile/android/config/tooltool-manifests/android/releng.manifest",
         "output_dir": "%(abs_work_dir)s/" + MOZILLA_DIR,
diff --git a/testing/mozharness/configs/single_locale/release_mozilla-release_android_api_15.py b/testing/mozharness/configs/single_locale/release_mozilla-release_android_api_15.py
index eaa2309e994f..22d0074bbae9 100644
--- a/testing/mozharness/configs/single_locale/release_mozilla-release_android_api_15.py
+++ b/testing/mozharness/configs/single_locale/release_mozilla-release_android_api_15.py
@@ -19,7 +19,7 @@ config = {
     "ignore_locales": ["en-US"],
     "balrog_credentials_file": "oauth.txt",
     "tools_repo": "https://hg.mozilla.org/build/tools",
-    "is_release": True,
+    "is_release_or_beta": True,
     "tooltool_config": {
         "manifest": "mobile/android/config/tooltool-manifests/android/releng.manifest",
         "output_dir": "%(abs_work_dir)s/" + MOZILLA_DIR,
diff --git a/testing/mozharness/configs/single_locale/staging_release_mozilla-beta_android_api_15.py b/testing/mozharness/configs/single_locale/staging_release_mozilla-beta_android_api_15.py
index fae2e89d9a87..7f7d3e4e27f5 100644
--- a/testing/mozharness/configs/single_locale/staging_release_mozilla-beta_android_api_15.py
+++ b/testing/mozharness/configs/single_locale/staging_release_mozilla-beta_android_api_15.py
@@ -19,7 +19,7 @@ config = {
     "ignore_locales": ["en-US"],
     "balrog_credentials_file": "oauth.txt",
     "tools_repo": "https://hg.mozilla.org/build/tools",
-    "is_release": True,
+    "is_release_or_beta": True,
     "tooltool_config": {
         "manifest": "mobile/android/config/tooltool-manifests/android/releng.manifest",
         "output_dir": "%(abs_work_dir)s/" + MOZILLA_DIR,
diff --git a/testing/mozharness/configs/single_locale/staging_release_mozilla-release_android_api_15.py b/testing/mozharness/configs/single_locale/staging_release_mozilla-release_android_api_15.py
index 7fed4f454302..da4803a60f4f 100644
--- a/testing/mozharness/configs/single_locale/staging_release_mozilla-release_android_api_15.py
+++ b/testing/mozharness/configs/single_locale/staging_release_mozilla-release_android_api_15.py
@@ -19,10 +19,7 @@ config = {
     "ignore_locales": ["en-US"],
     "balrog_credentials_file": "oauth.txt",
     "tools_repo": "https://hg.mozilla.org/build/tools",
-    "is_release": True,
-    "balrog_credentials_file": "oauth.txt",
-    "tools_repo": "https://hg.mozilla.org/build/tools",
-    "is_release": True,
+    "is_release_or_beta": True,
     "tooltool_config": {
         "manifest": "mobile/android/config/tooltool-manifests/android/releng.manifest",
         "output_dir": "%(abs_work_dir)s/" + MOZILLA_DIR,
diff --git a/testing/mozharness/scripts/mobile_l10n.py b/testing/mozharness/scripts/mobile_l10n.py
index 456947727e95..cbac6fa678f9 100755
--- a/testing/mozharness/scripts/mobile_l10n.py
+++ b/testing/mozharness/scripts/mobile_l10n.py
@@ -211,7 +211,7 @@ class MobileSingleLocale(MockMixin, LocalesMixin, ReleaseMixin,
                                     replace_dict=replace_dict)
         if 'MOZ_SIGNING_SERVERS' in os.environ:
             upload_env['MOZ_SIGN_CMD'] = subprocess.list2cmdline(self.query_moz_sign_cmd())
-        if self.query_is_release():
+        if self.query_is_release_or_beta():
             upload_env['MOZ_PKG_VERSION'] = '%(version)s' % replace_dict
         self.upload_env = upload_env
         return self.upload_env
@@ -649,13 +649,13 @@ class MobileSingleLocale(MockMixin, LocalesMixin, ReleaseMixin,
 
         return os.path.join(apkdir, apks[0])
 
-    def query_is_release(self):
+    def query_is_release_or_beta(self):
 
-        return bool(self.config.get("is_release"))
+        return bool(self.config.get("is_release_or_beta"))
 
     def submit_to_balrog(self):
 
-        if not self.query_is_nightly() and not self.query_is_release():
+        if not self.query_is_nightly() and not self.query_is_release_or_beta():
             self.info("Not a nightly or release build, skipping balrog submission.")
             return
 
diff --git a/testing/xpcshell/selftest.py b/testing/xpcshell/selftest.py
index 845a03cfb567..e725fcb6d925 100755
--- a/testing/xpcshell/selftest.py
+++ b/testing/xpcshell/selftest.py
@@ -858,7 +858,7 @@ add_test({
 
         self.assertTestResult(False)
         self.assertInLog(TEST_FAIL_STRING)
-        if not substs.get('RELEASE_BUILD'):
+        if not substs.get('RELEASE_OR_BETA'):
           # async stacks are currently not enabled in release builds.
           self.assertInLog("test_simple_uncaught_rejection.js:3:3")
         self.assertInLog("Test rejection.")
diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index 73fe32c201d0..f52917637cb7 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -79,7 +79,7 @@ const CATEGORY_EXTENSION_SCRIPTS_ADDON = "webextension-scripts-addon";
 
 let schemaURLs = new Set();
 
-if (!AppConstants.RELEASE_BUILD) {
+if (!AppConstants.RELEASE_OR_BETA) {
   schemaURLs.add("chrome://extensions/content/schemas/experiments.json");
 }
 
@@ -1530,7 +1530,7 @@ this.Extension = class extends ExtensionData {
 
   readManifest() {
     return super.readManifest().then(manifest => {
-      if (AppConstants.RELEASE_BUILD) {
+      if (AppConstants.RELEASE_OR_BETA) {
         return manifest;
       }
 
diff --git a/toolkit/components/extensions/ExtensionContent.jsm b/toolkit/components/extensions/ExtensionContent.jsm
index 0399a0e79792..4cc6d55a51ea 100644
--- a/toolkit/components/extensions/ExtensionContent.jsm
+++ b/toolkit/components/extensions/ExtensionContent.jsm
@@ -127,6 +127,13 @@ Script.prototype = {
 
   matches(window) {
     let uri = window.document.documentURIObject;
+
+    // If mozAddonManager is present on this page, don't allow
+    // content scripts.
+    if (window.navigator.mozAddonManager !== undefined) {
+      return false;
+    }
+
     if (!(this.matches_.matches(uri) || this.matches_host_.matchesIgnoringPath(uri))) {
       return false;
     }
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell.ini b/toolkit/components/extensions/test/xpcshell/xpcshell.ini
index 26a4918a7ffe..54199bef2a0b 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell.ini
@@ -32,7 +32,7 @@ skip-if = os == "android"
 [test_ext_downloads_search.js]
 skip-if = os == "android"
 [test_ext_experiments.js]
-skip-if = release_build
+skip-if = release_or_beta
 [test_ext_extension.js]
 [test_ext_idle.js]
 [test_ext_json_parser.js]
diff --git a/toolkit/components/telemetry/docs/internals/preferences.rst b/toolkit/components/telemetry/docs/internals/preferences.rst
index 177c61ce80e4..bd5e0ec00c99 100644
--- a/toolkit/components/telemetry/docs/internals/preferences.rst
+++ b/toolkit/components/telemetry/docs/internals/preferences.rst
@@ -25,8 +25,8 @@ Preferences
   If ``unified`` is on, this controls whether to record *extended* data.
   This preference is controlled through the `Preferences` dialog.
 
-  Note that the default value here of this pref depends on the define ``RELEASE_BUILD`` and the channel.
-  If ``RELEASE_BUILD`` is set, ``MOZ_TELEMETRY_ON_BY_DEFAULT`` gets set, which means this pref will default to ``true``.
+  Note that the default value here of this pref depends on the define ``RELEASE_OR_BETA`` and the channel.
+  If ``RELEASE_OR_BETA`` is set, ``MOZ_TELEMETRY_ON_BY_DEFAULT`` gets set, which means this pref will default to ``true``.
   This is overridden by the preferences code on the "beta" channel, the pref also defaults to ``true`` there.
 
 ``datareporting.healthreport.uploadEnabled``
diff --git a/toolkit/modules/AppConstants.jsm b/toolkit/modules/AppConstants.jsm
index ebbd143b4ddd..7ce8e1f09af4 100644
--- a/toolkit/modules/AppConstants.jsm
+++ b/toolkit/modules/AppConstants.jsm
@@ -22,8 +22,8 @@ this.AppConstants = Object.freeze({
   false,
 #endif
 
-  RELEASE_BUILD:
-#ifdef RELEASE_BUILD
+  RELEASE_OR_BETA:
+#ifdef RELEASE_OR_BETA
   true,
 #else
   false,
diff --git a/toolkit/modules/addons/WebRequest.jsm b/toolkit/modules/addons/WebRequest.jsm
index cc3000b4c7ee..b7c413ca04e8 100644
--- a/toolkit/modules/addons/WebRequest.jsm
+++ b/toolkit/modules/addons/WebRequest.jsm
@@ -688,7 +688,7 @@ var onBeforeRequest = {
   get allowedOptions() {
     delete this.allowedOptions;
     this.allowedOptions = ["blocking"];
-    if (!AppConstants.RELEASE_BUILD) {
+    if (!AppConstants.RELEASE_OR_BETA) {
       this.allowedOptions.push("requestBody");
     }
     return this.allowedOptions;
diff --git a/toolkit/modules/secondscreen/RokuApp.jsm b/toolkit/modules/secondscreen/RokuApp.jsm
index 496ab1cd1f3b..6b8d8181d902 100644
--- a/toolkit/modules/secondscreen/RokuApp.jsm
+++ b/toolkit/modules/secondscreen/RokuApp.jsm
@@ -25,7 +25,7 @@ const PROTOCOL_VERSION = 1;
 function RokuApp(service) {
   this.service = service;
   this.resourceURL = this.service.location;
-  this.app = AppConstants.RELEASE_BUILD ? "Firefox" : "Firefox Nightly";
+  this.app = AppConstants.RELEASE_OR_BETA ? "Firefox" : "Firefox Nightly";
   this.mediaAppID = -1;
 }
 
diff --git a/toolkit/mozapps/extensions/internal/XPIProvider.jsm b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
index 80d4cda57556..3d4f5944a7fe 100644
--- a/toolkit/mozapps/extensions/internal/XPIProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
@@ -230,7 +230,7 @@ const TYPES = {
   experiment: 128,
 };
 
-if (!AppConstants.RELEASE_BUILD)
+if (!AppConstants.RELEASE_OR_BETA)
   TYPES.apiextension = 256;
 
 // Some add-on types that we track internally are presented as other types
diff --git a/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js b/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
index 5711844a6513..9933ec0ea16a 100644
--- a/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
@@ -304,7 +304,7 @@ add_task(function* test_options_ui() {
 
 // Test that experiments permissions add the appropriate dependencies.
 add_task(function* test_experiments_dependencies() {
-  if (AppConstants.RELEASE_BUILD)
+  if (AppConstants.RELEASE_OR_BETA)
     // Experiments are not enabled on release builds.
     return;
 
@@ -329,7 +329,7 @@ add_task(function* test_experiments_dependencies() {
 
 // Test that experiments API extensions install correctly.
 add_task(function* test_experiments_api() {
-  if (AppConstants.RELEASE_BUILD)
+  if (AppConstants.RELEASE_OR_BETA)
     // Experiments are not enabled on release builds.
     return;
 
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 93f455cb6679..39143329aa28 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -1016,7 +1016,7 @@ nsXULAppInfo::GetLastRunCrashID(nsAString &aLastRunCrashID)
 NS_IMETHODIMP
 nsXULAppInfo::GetIsReleaseBuild(bool* aResult)
 {
-#ifdef RELEASE_BUILD
+#ifdef RELEASE_OR_BETA
   *aResult = true;
 #else
   *aResult = false;
@@ -4870,7 +4870,7 @@ MultiprocessBlockPolicy() {
   // For linux nightly and aurora builds skip accessibility
   // checks.
   bool doAccessibilityCheck = true;
-#if defined(MOZ_WIDGET_GTK) && !defined(RELEASE_BUILD)
+#if defined(MOZ_WIDGET_GTK) && !defined(RELEASE_OR_BETA)
   doAccessibilityCheck = false;
 #endif
 
diff --git a/widget/android/jni/Utils.h b/widget/android/jni/Utils.h
index 6753b661831a..38e0b6b0c889 100644
--- a/widget/android/jni/Utils.h
+++ b/widget/android/jni/Utils.h
@@ -5,7 +5,7 @@
 
 #include "mozilla/UniquePtr.h"
 
-#if defined(DEBUG) || !defined(RELEASE_BUILD)
+#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
 #define MOZ_CHECK_JNI
 #endif
 
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
index 66ba2de18bd7..7c995d900ae9 100644
--- a/widget/cocoa/moz.build
+++ b/widget/cocoa/moz.build
@@ -72,7 +72,7 @@ SOURCES += [
     'nsNativeThemeCocoa.mm',
 ]
 
-if not CONFIG['RELEASE_BUILD'] or CONFIG['MOZ_DEBUG']:
+if not CONFIG['RELEASE_OR_BETA'] or CONFIG['MOZ_DEBUG']:
     SOURCES += [
         'nsSandboxViolationSink.mm',
     ]
diff --git a/widget/cocoa/nsAppShell.mm b/widget/cocoa/nsAppShell.mm
index da4e4f526594..b57904389e49 100644
--- a/widget/cocoa/nsAppShell.mm
+++ b/widget/cocoa/nsAppShell.mm
@@ -33,7 +33,7 @@
 #include "mozilla/HangMonitor.h"
 #include "GeckoProfiler.h"
 #include "pratom.h"
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
 #include "nsSandboxViolationSink.h"
 #endif
 
@@ -322,7 +322,7 @@ nsAppShell::Init()
     CGSSetDebugOptions(0x80000007);
   }
 
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
   if (Preferences::GetBool("security.sandbox.mac.track.violations", false)) {
     nsSandboxViolationSink::Start();
   }
@@ -681,7 +681,7 @@ nsAppShell::Exit(void)
 
   mTerminated = true;
 
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
   nsSandboxViolationSink::Stop();
 #endif
 
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 78213b7841f8..64dea31a94da 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -5340,7 +5340,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
     [viewWindow orderWindow:NSWindowAbove relativeTo:0];
   }
 
-#if !defined(RELEASE_BUILD) || defined(DEBUG)
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
   if (!Preferences::GetBool("intl.allow-insecure-text-input", false) &&
       mGeckoChild && mTextInputHandler && mTextInputHandler->IsFocused()) {
 #ifdef MOZ_CRASHREPORTER
@@ -5372,7 +5372,7 @@ PanGestureTypeForEvent(NSEvent* aEvent)
       #undef CRASH_MESSAGE
     }
   }
-#endif // #if !defined(RELEASE_BUILD) || defined(DEBUG)
+#endif // #if !defined(RELEASE_OR_BETA) || defined(DEBUG)
 
   nsAutoRetainCocoaObject kungFuDeathGrip(self);
   bool handled = false;
diff --git a/xpcom/base/Logging.h b/xpcom/base/Logging.h
index ff8a0e64ac5b..040fb9c49720 100644
--- a/xpcom/base/Logging.h
+++ b/xpcom/base/Logging.h
@@ -31,7 +31,7 @@
 // devices, we've chosen to leave logging enabled on desktop, but disabled on
 // Android.  Given that logging can still be useful for development purposes,
 // however, we leave logging enabled on Android developer builds.
-#if !defined(ANDROID) || !defined(RELEASE_BUILD)
+#if !defined(ANDROID) || !defined(RELEASE_OR_BETA)
 #define MOZ_LOGGING_ENABLED 1
 #else
 #define MOZ_LOGGING_ENABLED 0
diff --git a/xpcom/build/IOInterposer.h b/xpcom/build/IOInterposer.h
index e5abc51a55f8..a07dfe9d947c 100644
--- a/xpcom/build/IOInterposer.h
+++ b/xpcom/build/IOInterposer.h
@@ -253,14 +253,14 @@ class IOInterposerInit
 public:
   IOInterposerInit()
   {
-#if !defined(RELEASE_BUILD)
+#if !defined(RELEASE_OR_BETA)
     IOInterposer::Init();
 #endif
   }
 
   ~IOInterposerInit()
   {
-#if !defined(RELEASE_BUILD)
+#if !defined(RELEASE_OR_BETA)
     IOInterposer::Clear();
 #endif
   }
diff --git a/xpcom/glue/nsCRTGlue.cpp b/xpcom/glue/nsCRTGlue.cpp
index 3438f46e1959..7a9f6db03031 100644
--- a/xpcom/glue/nsCRTGlue.cpp
+++ b/xpcom/glue/nsCRTGlue.cpp
@@ -321,7 +321,7 @@ set_stderr_callback(StderrCallback aCallback)
   sStderrCallback = aCallback;
 }
 
-#if defined(ANDROID) && !defined(RELEASE_BUILD)
+#if defined(ANDROID) && !defined(RELEASE_OR_BETA)
 static FILE* sStderrCopy = nullptr;
 
 void
diff --git a/xpcom/glue/nsDebug.h b/xpcom/glue/nsDebug.h
index 86495e47f0aa..7365f9ce34b4 100644
--- a/xpcom/glue/nsDebug.h
+++ b/xpcom/glue/nsDebug.h
@@ -426,14 +426,14 @@ void fprintf_stderr(FILE* aFile, const char* aFmt, ...) MOZ_FORMAT_PRINTF(2, 3);
 // advanced performance debugging and display/layers visualization.
 void set_stderr_callback(StderrCallback aCallback);
 
-#if defined(ANDROID) && !defined(RELEASE_BUILD)
+#if defined(ANDROID) && !defined(RELEASE_OR_BETA)
 // Call this if you want a copy of stderr logging sent to a file. This is
 // useful to get around logcat overflow problems on android devices, which use
 // a circular logcat buffer and can intermittently drop messages if there's too
 // much spew.
 //
 // This is intended for local debugging only, DO NOT USE IN PRODUCTION CODE.
-// (This is ifndef RELEASE_BUILD to catch uses of it that accidentally get
+// (This is ifndef RELEASE_OR_BETA to catch uses of it that accidentally get
 // checked in). Using this will also prevent the profiler from getting a copy of
 // the stderr messages which it uses for various visualization features.
 //
diff --git a/xpcom/system/nsIXULRuntime.idl b/xpcom/system/nsIXULRuntime.idl
index edb2d3e96fb2..128592fd4289 100644
--- a/xpcom/system/nsIXULRuntime.idl
+++ b/xpcom/system/nsIXULRuntime.idl
@@ -144,7 +144,7 @@ interface nsIXULRuntime : nsISupports
   readonly attribute DOMString lastRunCrashID;
 
   /**
-   * True if this is a RELEASE_BUILD.
+   * True if this is RELEASE_OR_BETA.
    */
   readonly attribute boolean isReleaseBuild;