diff --git a/dom/base/nsContentPolicyUtils.h b/dom/base/nsContentPolicyUtils.h
index 616e439fee95..bbb5c4c8ba6b 100644
--- a/dom/base/nsContentPolicyUtils.h
+++ b/dom/base/nsContentPolicyUtils.h
@@ -114,6 +114,7 @@ NS_CP_ContentTypeName(uint32_t contentType)
     CASE_RETURN( TYPE_FETCH                       );
     CASE_RETURN( TYPE_IMAGESET                    );
     CASE_RETURN( TYPE_WEB_MANIFEST                );
+    CASE_RETURN( TYPE_SAVEAS_DOWNLOAD             );
     CASE_RETURN( TYPE_INTERNAL_SCRIPT             );
     CASE_RETURN( TYPE_INTERNAL_WORKER             );
     CASE_RETURN( TYPE_INTERNAL_SHARED_WORKER      );
diff --git a/dom/base/nsIContentPolicy.idl b/dom/base/nsIContentPolicy.idl
index 3b0fe18a46a8..19a84ef89fdf 100644
--- a/dom/base/nsIContentPolicy.idl
+++ b/dom/base/nsIContentPolicy.idl
@@ -181,6 +181,11 @@ interface nsIContentPolicy : nsISupports
    */
   const nsContentPolicyType TYPE_WEB_MANIFEST = 22;
 
+  /**
+   * Indicates an save-as link download from the front-end code.
+   */
+  const nsContentPolicyType TYPE_SAVEAS_DOWNLOAD = 43;
+
   /**
    * Indicates an internal constant for scripts loaded through script
    * elements.
diff --git a/dom/cache/DBSchema.cpp b/dom/cache/DBSchema.cpp
index 38634b88aaa3..40ce654b7086 100644
--- a/dom/cache/DBSchema.cpp
+++ b/dom/cache/DBSchema.cpp
@@ -311,6 +311,7 @@ static_assert(nsIContentPolicy::TYPE_INVALID == 0 &&
               nsIContentPolicy::TYPE_FETCH == 20 &&
               nsIContentPolicy::TYPE_IMAGESET == 21 &&
               nsIContentPolicy::TYPE_WEB_MANIFEST == 22 &&
+              nsIContentPolicy::TYPE_SAVEAS_DOWNLOAD == 43 &&
               nsIContentPolicy::TYPE_INTERNAL_SCRIPT == 23 &&
               nsIContentPolicy::TYPE_INTERNAL_WORKER == 24 &&
               nsIContentPolicy::TYPE_INTERNAL_SHARED_WORKER == 25 &&
diff --git a/dom/fetch/InternalRequest.cpp b/dom/fetch/InternalRequest.cpp
index 9fe13d36e50a..11eea7919aad 100644
--- a/dom/fetch/InternalRequest.cpp
+++ b/dom/fetch/InternalRequest.cpp
@@ -324,6 +324,9 @@ InternalRequest::MapContentPolicyTypeToRequestContext(nsContentPolicyType aConte
   case nsIContentPolicy::TYPE_WEB_MANIFEST:
     context = RequestContext::Manifest;
     break;
+  case nsIContentPolicy::TYPE_SAVEAS_DOWNLOAD:
+    context = RequestContext::Internal;
+    break;
   default:
     MOZ_ASSERT(false, "Unhandled nsContentPolicyType value");
     break;
diff --git a/dom/fetch/InternalRequest.h b/dom/fetch/InternalRequest.h
index b09dd18f8a88..911efeb49173 100644
--- a/dom/fetch/InternalRequest.h
+++ b/dom/fetch/InternalRequest.h
@@ -53,7 +53,7 @@ namespace dom {
  * image             | TYPE_INTERNAL_IMAGE, TYPE_INTERNAL_IMAGE_PRELOAD, TYPE_INTERNAL_IMAGE_FAVICON
  * imageset          | TYPE_IMAGESET
  * import            | Not supported by Gecko
- * internal          | TYPE_DOCUMENT, TYPE_XBL, TYPE_OTHER
+ * internal          | TYPE_DOCUMENT, TYPE_XBL, TYPE_OTHER, TYPE_SAVEAS_DOWNLOAD
  * location          |
  * manifest          | TYPE_WEB_MANIFEST
  * object            | TYPE_INTERNAL_OBJECT
diff --git a/dom/security/nsContentSecurityManager.cpp b/dom/security/nsContentSecurityManager.cpp
index b4b96fe9a05c..2322a35bfa60 100644
--- a/dom/security/nsContentSecurityManager.cpp
+++ b/dom/security/nsContentSecurityManager.cpp
@@ -480,6 +480,12 @@ DoContentSecurityChecks(nsIChannel* aChannel, nsILoadInfo* aLoadInfo)
       break;
     }
 
+    case nsIContentPolicy::TYPE_SAVEAS_DOWNLOAD: {
+      mimeTypeGuess = EmptyCString();
+      requestingContext = aLoadInfo->LoadingNode();
+      break;
+    }
+
     default:
       // nsIContentPolicy::TYPE_INVALID
       MOZ_ASSERT(false, "can not perform security check without a valid contentType");
diff --git a/dom/security/nsMixedContentBlocker.cpp b/dom/security/nsMixedContentBlocker.cpp
index 13830424232c..ccc89e724ea5 100644
--- a/dom/security/nsMixedContentBlocker.cpp
+++ b/dom/security/nsMixedContentBlocker.cpp
@@ -576,6 +576,13 @@ nsMixedContentBlocker::ShouldLoad(bool aHadInsecureImageRedirect,
       *aDecision = ACCEPT;
       return NS_OK;
 
+    // Creating insecure connections for a save-as link download is acceptable.
+    // This download is completely disconnected from the docShell, but still
+    // using the same loading principal.
+    case TYPE_SAVEAS_DOWNLOAD:
+      *aDecision = ACCEPT;
+      return NS_OK;
+
     // Static display content is considered moderate risk for mixed content so
     // these will be blocked according to the mixed display preference
     case TYPE_IMAGE: