diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index 8a71a31afa93..9b63e050e175 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1484,6 +1484,8 @@ function _loadURI(browser, uri, params = {}) {
     params || {};
   let loadFlags =
     params.loadFlags || params.flags || Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
+  let hasValidUserGestureActivation =
+    document.hasValidTransientUserGestureActivation;
 
   if (!triggeringPrincipal) {
     throw new Error("Must load with a triggering Principal");
@@ -1525,6 +1527,7 @@ function _loadURI(browser, uri, params = {}) {
     loadFlags,
     referrerInfo,
     postData,
+    hasValidUserGestureActivation,
   };
   try {
     if (!mustChangeProcess) {
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 9b42c7b1207e..a58f9e850ed7 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3937,6 +3937,9 @@ nsresult nsDocShell::LoadErrorPage(nsIURI* aErrorURI, nsIURI* aFailedURI,
   loadState->SetLoadType(LOAD_ERROR_PAGE);
   loadState->SetFirstParty(true);
   loadState->SetSourceBrowsingContext(mBrowsingContext);
+  loadState->SetHasValidUserGestureActivation(
+      mBrowsingContext &&
+      mBrowsingContext->HasValidTransientUserGestureActivation());
 
   return InternalLoad(loadState, nullptr, nullptr);
 }
@@ -4041,6 +4044,9 @@ nsDocShell::Reload(uint32_t aReloadFlags) {
     loadState->SetSrcdocData(srcdoc);
     loadState->SetSourceBrowsingContext(mBrowsingContext);
     loadState->SetBaseURI(baseURI);
+    loadState->SetHasValidUserGestureActivation(
+        mBrowsingContext &&
+        mBrowsingContext->HasValidTransientUserGestureActivation());
     rv = InternalLoad(loadState, nullptr, nullptr);
   }
 
@@ -5115,6 +5121,8 @@ nsDocShell::ForceRefreshURI(nsIURI* aURI, nsIPrincipal* aPrincipal,
   loadState->SetTriggeringPrincipal(principal);
   if (doc) {
     loadState->SetCsp(doc->GetCsp());
+    loadState->SetHasValidUserGestureActivation(
+        doc->HasValidTransientUserGestureActivation());
   }
 
   loadState->SetPrincipalIsExplicit(true);
@@ -8273,6 +8281,9 @@ nsresult nsDocShell::PerformRetargeting(nsDocShellLoadState* aLoadState,
       loadState->SetForceAllowDataURI(
           aLoadState->HasLoadFlags(INTERNAL_LOAD_FLAGS_FORCE_ALLOW_DATA_URI));
 
+      loadState->SetHasValidUserGestureActivation(
+          aLoadState->HasValidUserGestureActivation());
+
       rv = win->Open(NS_ConvertUTF8toUTF16(spec),
                      aLoadState->Target(),  // window name
                      EmptyString(),         // Features
@@ -9758,6 +9769,15 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
                          Maybe<mozilla::dom::ServiceWorkerDescriptor>(),
                          sandboxFlags);
 
+  // in case this docshell load was triggered by a valid transient user gesture,
+  // or also the load originates from external, then we pass that information on
+  // to the loadinfo, which allows e.g. setting Sec-Fetch-User request headers.
+  if (mBrowsingContext->HasValidTransientUserGestureActivation() ||
+      aLoadState->HasValidUserGestureActivation() ||
+      aLoadState->HasLoadFlags(LOAD_FLAGS_FROM_EXTERNAL)) {
+    loadInfo->SetHasValidUserGestureActivation(true);
+  }
+
   /* Get the cache Key from SH */
   uint32_t cacheKey = 0;
   if (mLSHE) {
@@ -12203,6 +12223,9 @@ nsresult nsDocShell::OnLinkClickSync(
   loadState->SetFirstParty(true);
   loadState->SetSourceBrowsingContext(mBrowsingContext);
   loadState->SetIsFormSubmission(aContent->IsHTMLElement(nsGkAtoms::form));
+  loadState->SetHasValidUserGestureActivation(
+      mBrowsingContext &&
+      mBrowsingContext->HasValidTransientUserGestureActivation());
   nsresult rv = InternalLoad(loadState, aDocShell, aRequest);
 
   if (NS_SUCCEEDED(rv)) {
diff --git a/docshell/base/nsDocShellLoadState.cpp b/docshell/base/nsDocShellLoadState.cpp
index 2d54ab4c82cd..b69b0722cc82 100644
--- a/docshell/base/nsDocShellLoadState.cpp
+++ b/docshell/base/nsDocShellLoadState.cpp
@@ -42,6 +42,7 @@ nsDocShellLoadState::nsDocShellLoadState(nsIURI* aURI)
       mSrcdocData(VoidString()),
       mLoadFlags(0),
       mFirstParty(false),
+      mHasValidUserGestureActivation(false),
       mTypeHint(VoidCString()),
       mFileName(VoidString()),
       mIsFromProcessingFrameAttributes(false) {
@@ -64,6 +65,7 @@ nsDocShellLoadState::nsDocShellLoadState(
   mTarget = aLoadState.Target();
   mLoadFlags = aLoadState.LoadFlags();
   mFirstParty = aLoadState.FirstParty();
+  mHasValidUserGestureActivation = aLoadState.HasValidUserGestureActivation();
   mTypeHint = aLoadState.TypeHint();
   mFileName = aLoadState.FileName();
   mIsFromProcessingFrameAttributes =
@@ -265,6 +267,8 @@ nsresult nsDocShellLoadState::CreateFromLoadURIOptions(
 
   loadState->SetLoadFlags(extraFlags);
   loadState->SetFirstParty(true);
+  loadState->SetHasValidUserGestureActivation(
+      aLoadURIOptions.mHasValidUserGestureActivation);
   loadState->SetPostDataStream(postData);
   loadState->SetHeadersStream(aLoadURIOptions.mHeaders);
   loadState->SetBaseURI(aLoadURIOptions.mBaseURI);
@@ -492,6 +496,15 @@ void nsDocShellLoadState::SetFirstParty(bool aFirstParty) {
   mFirstParty = aFirstParty;
 }
 
+bool nsDocShellLoadState::HasValidUserGestureActivation() const {
+  return mHasValidUserGestureActivation;
+}
+
+void nsDocShellLoadState::SetHasValidUserGestureActivation(
+    bool aHasValidUserGestureActivation) {
+  mHasValidUserGestureActivation = aHasValidUserGestureActivation;
+}
+
 const nsCString& nsDocShellLoadState::TypeHint() const { return mTypeHint; }
 
 void nsDocShellLoadState::SetTypeHint(const nsCString& aTypeHint) {
@@ -662,6 +675,7 @@ DocShellLoadStateInit nsDocShellLoadState::Serialize() {
   loadState.Target() = mTarget;
   loadState.LoadFlags() = mLoadFlags;
   loadState.FirstParty() = mFirstParty;
+  loadState.HasValidUserGestureActivation() = mHasValidUserGestureActivation;
   loadState.TypeHint() = mTypeHint;
   loadState.FileName() = mFileName;
   loadState.IsFromProcessingFrameAttributes() =
diff --git a/docshell/base/nsDocShellLoadState.h b/docshell/base/nsDocShellLoadState.h
index 7aaba7b0a8a7..ef486437de23 100644
--- a/docshell/base/nsDocShellLoadState.h
+++ b/docshell/base/nsDocShellLoadState.h
@@ -177,6 +177,10 @@ class nsDocShellLoadState final {
 
   void SetFirstParty(bool aFirstParty);
 
+  bool HasValidUserGestureActivation() const;
+
+  void SetHasValidUserGestureActivation(bool HasValidUserGestureActivation);
+
   const nsCString& TypeHint() const;
 
   void SetTypeHint(const nsCString& aTypeHint);
@@ -355,6 +359,9 @@ class nsDocShellLoadState final {
   // Is this a First Party Load?
   bool mFirstParty;
 
+  // Is this load triggered by a user gesture?
+  bool mHasValidUserGestureActivation;
+
   // A hint as to the content-type of the resulting data. If no hint, IsVoid()
   // should return true.
   nsCString mTypeHint;
diff --git a/dom/base/LocationBase.cpp b/dom/base/LocationBase.cpp
index 5397eea792cb..2432c9a4d794 100644
--- a/dom/base/LocationBase.cpp
+++ b/dom/base/LocationBase.cpp
@@ -103,6 +103,8 @@ already_AddRefed<nsDocShellLoadState> LocationBase::CheckURL(
   if (referrerInfo) {
     loadState->SetReferrerInfo(referrerInfo);
   }
+  loadState->SetHasValidUserGestureActivation(
+      doc->HasValidTransientUserGestureActivation());
 
   return loadState.forget();
 }
@@ -130,7 +132,10 @@ void LocationBase::SetURI(nsIURI* aURI, nsIPrincipal& aSubjectPrincipal,
   nsCOMPtr<nsPIDOMWindowInner> sourceWindow =
       nsContentUtils::CallerInnerWindow();
   if (sourceWindow) {
-    loadState->SetSourceBrowsingContext(sourceWindow->GetBrowsingContext());
+    RefPtr<BrowsingContext> sourceBC = sourceWindow->GetBrowsingContext();
+    loadState->SetSourceBrowsingContext(sourceBC);
+    loadState->SetHasValidUserGestureActivation(
+        sourceBC && sourceBC->HasValidTransientUserGestureActivation());
   }
 
   loadState->SetLoadFlags(nsIWebNavigation::LOAD_FLAGS_NONE);
diff --git a/dom/clients/manager/ClientNavigateOpChild.cpp b/dom/clients/manager/ClientNavigateOpChild.cpp
index 867a362b456f..a8bcb094cd06 100644
--- a/dom/clients/manager/ClientNavigateOpChild.cpp
+++ b/dom/clients/manager/ClientNavigateOpChild.cpp
@@ -258,6 +258,8 @@ RefPtr<ClientOpPromise> ClientNavigateOpChild::DoNavigate(
   loadState->SetSourceBrowsingContext(docShell->GetBrowsingContext());
   loadState->SetLoadFlags(nsIWebNavigation::LOAD_FLAGS_NONE);
   loadState->SetFirstParty(true);
+  loadState->SetHasValidUserGestureActivation(
+      doc->HasValidTransientUserGestureActivation());
   rv = docShell->LoadURI(loadState, false);
   if (NS_FAILED(rv)) {
     /// There are tests that try sending file:/// and mixed-content URLs
diff --git a/dom/ipc/DOMTypes.ipdlh b/dom/ipc/DOMTypes.ipdlh
index 6780a87c8318..6d4cc6520fd4 100644
--- a/dom/ipc/DOMTypes.ipdlh
+++ b/dom/ipc/DOMTypes.ipdlh
@@ -255,6 +255,7 @@ struct DocShellLoadStateInit
   nsIURI BaseURI;
   uint32_t LoadFlags;
   bool FirstParty;
+  bool HasValidUserGestureActivation;
   nsCString TypeHint;
   nsString FileName;
   bool IsFromProcessingFrameAttributes;
diff --git a/dom/security/SecFetch.cpp b/dom/security/SecFetch.cpp
index 6a5951292b0b..3321092052d8 100644
--- a/dom/security/SecFetch.cpp
+++ b/dom/security/SecFetch.cpp
@@ -288,12 +288,24 @@ void SecFetch::AddSecFetchSite(nsIHttpChannel* aHTTPChannel) {
 }
 
 void SecFetch::AddSecFetchUser(nsIHttpChannel* aHTTPChannel) {
-  // TODO: Bug 1621987: Implement Sec-Fetch-User
+  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
+  nsContentPolicyType externalType = loadInfo->GetExternalContentPolicyType();
 
-  // nsAutoCString user("?1");
-  // nsresult rv = aHTTPChannel->SetRequestHeader(
-  //     NS_LITERAL_CSTRING("Sec-Fetch-User"), user, false);
-  // Unused << NS_WARN_IF(NS_FAILED(rv));
+  // sec-fetch-user only applies to loads of type document or subdocument
+  if (externalType != nsIContentPolicy::TYPE_DOCUMENT &&
+      externalType != nsIContentPolicy::TYPE_SUBDOCUMENT) {
+    return;
+  }
+
+  // sec-fetch-user only applies if the request is user triggered
+  if (!loadInfo->GetHasValidUserGestureActivation()) {
+    return;
+  }
+
+  nsAutoCString user("?1");
+  nsresult rv = aHTTPChannel->SetRequestHeader(
+      NS_LITERAL_CSTRING("Sec-Fetch-User"), user, false);
+  Unused << NS_WARN_IF(NS_FAILED(rv));
 }
 
 void SecFetch::AddSecFetchHeader(nsIHttpChannel* aHTTPChannel) {
diff --git a/dom/webidl/LoadURIOptions.webidl b/dom/webidl/LoadURIOptions.webidl
index 27368717b3a3..7cb05dbf7df2 100644
--- a/dom/webidl/LoadURIOptions.webidl
+++ b/dom/webidl/LoadURIOptions.webidl
@@ -62,6 +62,12 @@ dictionary LoadURIOptions {
    */
   URI? baseURI = null;
 
+  /**
+   * Set to indicate that the URI to be loaded was triggered by a user
+   * action. (Mostly used in the context of Sec-Fetch-User).
+   */
+  boolean hasValidUserGestureActivation = false;
+
   /**
    * If non-0, a value to pass to nsIDocShell::setCancelContentJSEpoch
    * when initiating the load.
diff --git a/ipc/glue/BackgroundUtils.cpp b/ipc/glue/BackgroundUtils.cpp
index c014f316744a..a551e00bcfa3 100644
--- a/ipc/glue/BackgroundUtils.cpp
+++ b/ipc/glue/BackgroundUtils.cpp
@@ -546,6 +546,7 @@ nsresult LoadInfoToLoadInfoArgs(nsILoadInfo* aLoadInfo,
       aLoadInfo->GetAllowListFutureDocumentsCreatedFromThisRedirectChain(),
       cspNonce, aLoadInfo->GetSkipContentSniffing(),
       aLoadInfo->GetHttpsOnlyStatus(),
+      aLoadInfo->GetHasValidUserGestureActivation(),
       aLoadInfo->GetAllowDeprecatedSystemRequests(),
       aLoadInfo->GetParserCreatedScript(),
       aLoadInfo->GetIsFromProcessingFrameAttributes(), cookieJarSettingsArgs,
@@ -747,6 +748,7 @@ nsresult LoadInfoArgsToLoadInfo(
       loadInfoArgs.allowListFutureDocumentsCreatedFromThisRedirectChain(),
       loadInfoArgs.cspNonce(), loadInfoArgs.skipContentSniffing(),
       loadInfoArgs.httpsOnlyStatus(),
+      loadInfoArgs.hasValidUserGestureActivation(),
       loadInfoArgs.allowDeprecatedSystemRequests(),
       loadInfoArgs.parserCreatedScript(), loadInfoArgs.hasStoragePermission(),
       loadInfoArgs.requestBlockingReason(), loadingContext);
@@ -787,6 +789,7 @@ void LoadInfoToParentLoadInfoForwarder(
       aLoadInfo->GetAllowInsecureRedirectToDataURI(),
       aLoadInfo->GetBypassCORSChecks(), ipcController, tainting,
       aLoadInfo->GetSkipContentSniffing(), aLoadInfo->GetHttpsOnlyStatus(),
+      aLoadInfo->GetHasValidUserGestureActivation(),
       aLoadInfo->GetAllowDeprecatedSystemRequests(),
       aLoadInfo->GetParserCreatedScript(),
       aLoadInfo->GetServiceWorkerTaintingSynthesized(),
@@ -827,6 +830,10 @@ nsresult MergeParentLoadInfoForwarder(
   rv = aLoadInfo->SetHttpsOnlyStatus(aForwarderArgs.httpsOnlyStatus());
   NS_ENSURE_SUCCESS(rv, rv);
 
+  rv = aLoadInfo->SetHasValidUserGestureActivation(
+      aForwarderArgs.hasValidUserGestureActivation());
+  NS_ENSURE_SUCCESS(rv, rv);
+
   rv = aLoadInfo->SetAllowDeprecatedSystemRequests(
       aForwarderArgs.allowDeprecatedSystemRequests());
   NS_ENSURE_SUCCESS(rv, rv);
diff --git a/netwerk/base/LoadInfo.cpp b/netwerk/base/LoadInfo.cpp
index 25a2e55aa7bf..554d21182204 100644
--- a/netwerk/base/LoadInfo.cpp
+++ b/netwerk/base/LoadInfo.cpp
@@ -106,6 +106,7 @@ LoadInfo::LoadInfo(
       mAllowListFutureDocumentsCreatedFromThisRedirectChain(false),
       mSkipContentSniffing(false),
       mHttpsOnlyStatus(nsILoadInfo::HTTPS_ONLY_UNINITIALIZED),
+      mHasValidUserGestureActivation(false),
       mAllowDeprecatedSystemRequests(false),
       mParserCreatedScript(false),
       mHasStoragePermission(false),
@@ -380,6 +381,7 @@ LoadInfo::LoadInfo(nsPIDOMWindowOuter* aOuterWindow,
       mAllowListFutureDocumentsCreatedFromThisRedirectChain(false),
       mSkipContentSniffing(false),
       mHttpsOnlyStatus(nsILoadInfo::HTTPS_ONLY_UNINITIALIZED),
+      mHasValidUserGestureActivation(false),
       mAllowDeprecatedSystemRequests(false),
       mParserCreatedScript(false),
       mHasStoragePermission(false),
@@ -484,6 +486,7 @@ LoadInfo::LoadInfo(dom::CanonicalBrowsingContext* aBrowsingContext,
       mAllowListFutureDocumentsCreatedFromThisRedirectChain(false),
       mSkipContentSniffing(false),
       mHttpsOnlyStatus(nsILoadInfo::HTTPS_ONLY_UNINITIALIZED),
+      mHasValidUserGestureActivation(false),
       mAllowDeprecatedSystemRequests(false),
       mParserCreatedScript(false),
       mHasStoragePermission(false),
@@ -777,6 +780,7 @@ LoadInfo::LoadInfo(const LoadInfo& rhs)
       mCspNonce(rhs.mCspNonce),
       mSkipContentSniffing(rhs.mSkipContentSniffing),
       mHttpsOnlyStatus(rhs.mHttpsOnlyStatus),
+      mHasValidUserGestureActivation(rhs.mHasValidUserGestureActivation),
       mAllowDeprecatedSystemRequests(rhs.mAllowDeprecatedSystemRequests),
       mParserCreatedScript(rhs.mParserCreatedScript),
       mHasStoragePermission(rhs.mHasStoragePermission),
@@ -817,9 +821,10 @@ LoadInfo::LoadInfo(
     bool aDocumentHasLoaded,
     bool aAllowListFutureDocumentsCreatedFromThisRedirectChain,
     const nsAString& aCspNonce, bool aSkipContentSniffing,
-    uint32_t aHttpsOnlyStatus, bool aAllowDeprecatedSystemRequests,
-    bool aParserCreatedScript, bool aHasStoragePermission,
-    uint32_t aRequestBlockingReason, nsINode* aLoadingContext)
+    uint32_t aHttpsOnlyStatus, bool aHasValidUserGestureActivation,
+    bool aAllowDeprecatedSystemRequests, bool aParserCreatedScript,
+    bool aHasStoragePermission, uint32_t aRequestBlockingReason,
+    nsINode* aLoadingContext)
     : mLoadingPrincipal(aLoadingPrincipal),
       mTriggeringPrincipal(aTriggeringPrincipal),
       mPrincipalToInherit(aPrincipalToInherit),
@@ -876,6 +881,7 @@ LoadInfo::LoadInfo(
       mCspNonce(aCspNonce),
       mSkipContentSniffing(aSkipContentSniffing),
       mHttpsOnlyStatus(aHttpsOnlyStatus),
+      mHasValidUserGestureActivation(aHasValidUserGestureActivation),
       mAllowDeprecatedSystemRequests(aAllowDeprecatedSystemRequests),
       mParserCreatedScript(aParserCreatedScript),
       mHasStoragePermission(aHasStoragePermission),
@@ -1725,6 +1731,20 @@ LoadInfo::SetHttpsOnlyStatus(uint32_t aHttpsOnlyStatus) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+LoadInfo::GetHasValidUserGestureActivation(
+    bool* aHasValidUserGestureActivation) {
+  *aHasValidUserGestureActivation = mHasValidUserGestureActivation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LoadInfo::SetHasValidUserGestureActivation(
+    bool aHasValidUserGestureActivation) {
+  mHasValidUserGestureActivation = aHasValidUserGestureActivation;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 LoadInfo::GetAllowDeprecatedSystemRequests(
     bool* aAllowDeprecatedSystemRequests) {
diff --git a/netwerk/base/LoadInfo.h b/netwerk/base/LoadInfo.h
index a00d30f7160d..bd70ee17ed55 100644
--- a/netwerk/base/LoadInfo.h
+++ b/netwerk/base/LoadInfo.h
@@ -169,9 +169,10 @@ class LoadInfo final : public nsILoadInfo {
            bool aDocumentHasUserInteracted, bool aDocumentHasLoaded,
            bool aAllowListFutureDocumentsCreatedFromThisRedirectChain,
            const nsAString& aCspNonce, bool aSkipContentSniffing,
-           uint32_t aHttpsOnlyStatus, bool aAllowDeprecatedSystemRequests,
-           bool aParserCreatedScript, bool aHasStoragePermission,
-           uint32_t aRequestBlockingReason, nsINode* aLoadingContext);
+           uint32_t aHttpsOnlyStatus, bool aHasValidUserGestureActivation,
+           bool aAllowDeprecatedSystemRequests, bool aParserCreatedScript,
+           bool aHasStoragePermission, uint32_t aRequestBlockingReason,
+           nsINode* aLoadingContext);
   LoadInfo(const LoadInfo& rhs);
 
   NS_IMETHOD GetRedirects(JSContext* aCx,
@@ -268,6 +269,7 @@ class LoadInfo final : public nsILoadInfo {
   nsString mCspNonce;
   bool mSkipContentSniffing;
   uint32_t mHttpsOnlyStatus;
+  bool mHasValidUserGestureActivation;
   bool mAllowDeprecatedSystemRequests;
   bool mParserCreatedScript;
   bool mHasStoragePermission;
diff --git a/netwerk/base/TRRLoadInfo.cpp b/netwerk/base/TRRLoadInfo.cpp
index 319e2bc59880..10d3a9637667 100644
--- a/netwerk/base/TRRLoadInfo.cpp
+++ b/netwerk/base/TRRLoadInfo.cpp
@@ -606,6 +606,18 @@ TRRLoadInfo::SetHttpsOnlyStatus(uint32_t aHttpsOnlyStatus) {
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP
+TRRLoadInfo::GetHasValidUserGestureActivation(
+    bool* aHasValidUserGestureActivation) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+TRRLoadInfo::SetHasValidUserGestureActivation(
+    bool aHasValidUserGestureActivation) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 NS_IMETHODIMP
 TRRLoadInfo::GetInternalContentPolicyType(nsContentPolicyType* aResult) {
   *aResult = mInternalContentPolicyType;
diff --git a/netwerk/base/nsILoadInfo.idl b/netwerk/base/nsILoadInfo.idl
index bb26e4628f63..f0575b60f61d 100644
--- a/netwerk/base/nsILoadInfo.idl
+++ b/netwerk/base/nsILoadInfo.idl
@@ -457,6 +457,14 @@ interface nsILoadInfo : nsISupports
    */
   [infallible] attribute unsigned long httpsOnlyStatus;
 
+  /**
+   * Returns true if at the time of the loadinfo construction the document
+   * that triggered this load has the bit hasValidTransientUserGestureActivation
+   * set or the load was triggered from External. (Mostly this bool is used
+   * in the context of Sec-Fetch-User.)
+   */
+  [infallible] attribute boolean hasValidUserGestureActivation;
+
   /**
    * We disallow the SystemPrincipal to initiate requests to
    * the public web. This flag is to allow exceptions.
diff --git a/netwerk/ipc/DocumentLoadListener.cpp b/netwerk/ipc/DocumentLoadListener.cpp
index 769f036b8c73..5f4d76262021 100644
--- a/netwerk/ipc/DocumentLoadListener.cpp
+++ b/netwerk/ipc/DocumentLoadListener.cpp
@@ -289,19 +289,22 @@ already_AddRefed<LoadInfo> DocumentLoadListener::CreateLoadInfo(
     securityFlags |= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
   }
 
+  RefPtr<LoadInfo> loadInfo;
   if (aBrowsingContext->GetParent()) {
     // Build LoadInfo for TYPE_SUBDOCUMENT
-    RefPtr<LoadInfo> loadInfo =
-        new LoadInfo(aBrowsingContext, aLoadState->TriggeringPrincipal(),
-                     aOuterWindowId, securityFlags, sandboxFlags);
-    return loadInfo.forget();
+    loadInfo = new LoadInfo(aBrowsingContext, aLoadState->TriggeringPrincipal(),
+                            aOuterWindowId, securityFlags, sandboxFlags);
+  } else {
+    // Build LoadInfo for TYPE_DOCUMENT
+    OriginAttributes attrs;
+    mLoadContext->GetOriginAttributes(attrs);
+    loadInfo = new LoadInfo(aBrowsingContext, aLoadState->TriggeringPrincipal(),
+                            attrs, aOuterWindowId, securityFlags, sandboxFlags);
   }
-  // Build LoadInfo for TYPE_DOCUMENT
-  OriginAttributes attrs;
-  mLoadContext->GetOriginAttributes(attrs);
-  RefPtr<LoadInfo> loadInfo =
-      new LoadInfo(aBrowsingContext, aLoadState->TriggeringPrincipal(), attrs,
-                   aOuterWindowId, securityFlags, sandboxFlags);
+
+  loadInfo->SetHasValidUserGestureActivation(
+      aLoadState->HasValidUserGestureActivation());
+
   return loadInfo.forget();
 }
 
diff --git a/netwerk/ipc/NeckoChannelParams.ipdlh b/netwerk/ipc/NeckoChannelParams.ipdlh
index 802929c575ae..9fb2e2135222 100644
--- a/netwerk/ipc/NeckoChannelParams.ipdlh
+++ b/netwerk/ipc/NeckoChannelParams.ipdlh
@@ -146,6 +146,7 @@ struct LoadInfoArgs
   nsString                    cspNonce;
   bool                        skipContentSniffing;
   uint32_t                    httpsOnlyStatus;
+  bool                        hasValidUserGestureActivation;
   bool                        allowDeprecatedSystemRequests;
   bool                        parserCreatedScript;
   bool                        isFromProcessingFrameAttributes;
@@ -189,6 +190,12 @@ struct ParentLoadInfoForwarderArgs
 
   uint32_t httpsOnlyStatus;
 
+  // Returns true if at the time of the loadinfo construction the document
+  // that triggered this load has the bit hasValidTransientUserGestureActivation
+  // set or the load was triggered from External. (Mostly this bool is used
+  // in the context of Sec-Fetch-User.)
+  bool hasValidUserGestureActivation;
+
   // The SystemPrincipal is disallowed to make requests to the public web
   // and all requests will be cancelled. Setting this flag to true prevents
   // the request from being cancelled.
diff --git a/testing/web-platform/meta/fetch/metadata/form.https.sub.html.ini b/testing/web-platform/meta/fetch/metadata/form.https.sub.html.ini
deleted file mode 100644
index e5fda980207d..000000000000
--- a/testing/web-platform/meta/fetch/metadata/form.https.sub.html.ini
+++ /dev/null
@@ -1,9 +0,0 @@
-[form.https.sub.html]
-  [web-platform.test -> web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
-
-  [web-platform.test -> www.web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
-
-  [web-platform.test -> www.not-web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
diff --git a/testing/web-platform/meta/fetch/metadata/iframe.https.sub.html.ini b/testing/web-platform/meta/fetch/metadata/iframe.https.sub.html.ini
deleted file mode 100644
index 4ccc958a9e03..000000000000
--- a/testing/web-platform/meta/fetch/metadata/iframe.https.sub.html.ini
+++ /dev/null
@@ -1,9 +0,0 @@
-[iframe.https.sub.html]
-  [web-platform.test -> web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
-
-  [web-platform.test -> www.web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
-
-  [web-platform.test -> www.not-web-platform.test:8443 iframe: user-activated: sec-fetch-user]
-    expected: FAIL
diff --git a/testing/web-platform/meta/fetch/metadata/window-open.https.sub.html.ini b/testing/web-platform/meta/fetch/metadata/window-open.https.sub.html.ini
index b1d3ea48a6b5..53da52b63012 100644
--- a/testing/web-platform/meta/fetch/metadata/window-open.https.sub.html.ini
+++ b/testing/web-platform/meta/fetch/metadata/window-open.https.sub.html.ini
@@ -1,16 +1,7 @@
 [window-open.https.sub.html]
-  [Cross-site window, user-activated: sec-fetch-user]
-    expected: FAIL
-
   [Cross-site window, forced, reloaded]
     expected: [PASS, FAIL]
 
-  [Same-origin window, user-activated: sec-fetch-user]
-    expected: FAIL
-
-  [Same-site window, user-activated: sec-fetch-user]
-    expected: FAIL
-
   [Same-site window, forced, reloaded]
     expected:
       if os == "android": ["PASS", "FAIL"]
diff --git a/toolkit/components/windowwatcher/nsWindowWatcher.cpp b/toolkit/components/windowwatcher/nsWindowWatcher.cpp
index 4479a018c628..c174643a37a2 100644
--- a/toolkit/components/windowwatcher/nsWindowWatcher.cpp
+++ b/toolkit/components/windowwatcher/nsWindowWatcher.cpp
@@ -1147,6 +1147,8 @@ nsresult nsWindowWatcher::OpenWindowInternal(
     loadState = new nsDocShellLoadState(uriToLoad);
 
     loadState->SetSourceBrowsingContext(parentBC);
+    loadState->SetHasValidUserGestureActivation(
+        parentBC && parentBC->HasValidTransientUserGestureActivation());
 
     if (subjectPrincipal) {
       loadState->SetTriggeringPrincipal(subjectPrincipal);