diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index cada0f58efbd..317cc73b1aae 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -4,7 +4,7 @@
 
 "use strict";
 
-this.EXPORTED_SYMBOLS = ["Extension", "ExtensionData", "InternalTestAPI"];
+this.EXPORTED_SYMBOLS = ["Extension", "ExtensionData"];
 
 /* globals Extension ExtensionData */
 
@@ -1555,13 +1555,3 @@ Extension.prototype = extend(Object.create(ExtensionData.prototype), {
     return this.localize(this.manifest.name);
   },
 });
-
-// Expose a limited subset of the Management API for testing.
-this.InternalTestAPI = {
-  on(...args) {
-    return Management.on(...args);
-  },
-  off(...args) {
-    return Management.off(...args);
-  },
-};
diff --git a/toolkit/components/extensions/ExtensionUtils.jsm b/toolkit/components/extensions/ExtensionUtils.jsm
index 044a32b3b9cd..f32336a75e29 100644
--- a/toolkit/components/extensions/ExtensionUtils.jsm
+++ b/toolkit/components/extensions/ExtensionUtils.jsm
@@ -1409,7 +1409,7 @@ class ChildAPIManager {
   }
 
   close() {
-    this.messageManager.sendAsyncMessage("API:CloseProxyContext", {childId: this.id});
+    this.messageManager.sendAsyncMessage("Extension:CloseProxyContext", {childId: this.id});
   }
 
   get cloneScope() {
diff --git a/toolkit/components/extensions/test/mochitest/file_teardown_test.js b/toolkit/components/extensions/test/mochitest/file_teardown_test.js
deleted file mode 100644
index 78543202d1ef..000000000000
--- a/toolkit/components/extensions/test/mochitest/file_teardown_test.js
+++ /dev/null
@@ -1,24 +0,0 @@
-"use strict";
-
-/* globals addMessageListener */
-let {InternalTestAPI} = Components.utils.import("resource://gre/modules/Extension.jsm");
-let events = [];
-function record(type, extensionContext) {
-  let eventType = type == "page-load" ? "load" : "unload";
-  let url = extensionContext.uri.spec;
-  let {extensionId} = extensionContext;
-  events.push({eventType, url, extensionId});
-}
-
-InternalTestAPI.on("page-load", record);
-InternalTestAPI.on("page-unload", record);
-addMessageListener("cleanup", () => {
-  InternalTestAPI.off("page-load", record);
-  InternalTestAPI.off("page-unload", record);
-});
-
-addMessageListener("get-context-events", extensionId => {
-  sendAsyncMessage("context-events", events);
-  events = [];
-});
-sendAsyncMessage("chromescript-startup");
diff --git a/toolkit/components/extensions/test/mochitest/mochitest.ini b/toolkit/components/extensions/test/mochitest/mochitest.ini
index 4bc7933307b3..23a9daa5b0bb 100644
--- a/toolkit/components/extensions/test/mochitest/mochitest.ini
+++ b/toolkit/components/extensions/test/mochitest/mochitest.ini
@@ -34,7 +34,6 @@ support-files =
   file_privilege_escalation.html
   file_ext_test_api_injection.js
   file_permission_xhr.html
-  file_teardown_test.js
 
 [test_ext_inIncognitoContext_window.html]
 skip-if = os == 'android' # Android does not currently support windows.
@@ -48,7 +47,6 @@ skip-if = buildapp == 'b2g' # runat != document_idle is not supported.
 [test_ext_contentscript_devtools_metadata.html]
 [test_ext_contentscript_exporthelpers.html]
 [test_ext_contentscript_css.html]
-[test_ext_contentscript_teardown.html]
 [test_ext_exclude_include_globs.html]
 [test_ext_i18n_css.html]
 [test_ext_generate.html]
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_teardown.html b/toolkit/components/extensions/test/mochitest/test_ext_contentscript_teardown.html
deleted file mode 100644
index b53dfc271d33..000000000000
--- a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_teardown.html
+++ /dev/null
@@ -1,98 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test for content script teardown</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/SpawnTask.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/ExtensionTestUtils.js"></script>
-  <script type="text/javascript" src="head.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
-</head>
-<body>
-
-<script>
-"use strict";
-
-add_task(function* test_contentscript_reload_and_unload() {
-  function contentScript() {
-    browser.test.sendMessage("contentscript-run");
-  }
-  function backgroundScript() {
-    let removedTabs = 0;
-    browser.tabs.onRemoved.addListener(() => {
-      browser.test.assertEq(1, ++removedTabs,
-          "Expected only one tab to be removed during the test");
-      browser.test.sendMessage("tab-closed");
-    });
-    browser.test.sendMessage("background-ready");
-  }
-
-  let extensionData = {
-    background: `(${backgroundScript})();`,
-    manifest: {
-      content_scripts: [{
-        "matches": ["http://mochi.test/*/file_sample.html"],
-        "js": ["contentscript.js"],
-      }],
-    },
-
-    files: {
-      "contentscript.js": `(${contentScript})();`,
-    },
-  };
-
-  let extension = ExtensionTestUtils.loadExtension(extensionData);
-  yield extension.startup();
-  yield extension.awaitMessage("background-ready");
-
-  let chromeScript = SpecialPowers.loadChromeScript(
-      SimpleTest.getTestFileURL("file_teardown_test.js"));
-  yield chromeScript.promiseOneMessage("chromescript-startup");
-  function* getContextEvents() {
-    chromeScript.sendAsyncMessage("get-context-events");
-    let contextEvents = yield chromeScript.promiseOneMessage("context-events");
-    return contextEvents.filter(event => event.extensionId == extension.id);
-  }
-
-  let win = window.open("file_sample.html");
-  yield extension.awaitMessage("contentscript-run");
-  let tabUrl = win.location.href;
-
-  let contextEvents = yield* getContextEvents();
-  is(contextEvents.length, 1,
-      "ExtensionContext state change after loading a content script");
-  is(contextEvents[0].eventType, "load",
-      "Create ExtensionContext for content script");
-  is(contextEvents[0].url, tabUrl, "ExtensionContext URL = page");
-
-  let promiseReload = extension.awaitMessage("contentscript-run");
-  win.location.reload();
-  yield promiseReload;
-  contextEvents = yield* getContextEvents();
-  is(contextEvents.length, 2,
-      "ExtensionContext state changes after reloading a content script");
-  is(contextEvents[0].eventType, "unload", "Unload old ExtensionContext");
-  is(contextEvents[0].url, tabUrl, "ExtensionContext URL = page");
-  is(contextEvents[1].eventType, "load",
-      "Create new ExtensionContext for content script");
-  is(contextEvents[1].url, tabUrl, "ExtensionContext URL = page");
-
-  let tabClosePromise = extension.awaitMessage("tab-closed");
-  win.close();
-  yield tabClosePromise;
-
-  contextEvents = yield* getContextEvents();
-  is(contextEvents.length, 1,
-      "ExtensionContext state change after unloading a content script");
-  is(contextEvents[0].eventType, "unload",
-      "Unload ExtensionContext after closing the tab with the content script");
-  is(contextEvents[0].url, tabUrl, "ExtensionContext URL = page");
-
-  chromeScript.sendAsyncMessage("cleanup");
-  chromeScript.destroy();
-  yield extension.unload();
-});
-</script>
-
-</body>
-</html>
