--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -220,30 +220,30 @@ partial interface Document {
 };
 
 // https://fullscreen.spec.whatwg.org/#api
 partial interface Document {
   // Note: Per spec the 'S' in these two is lowercase, but the "Moz"
   // versions have it uppercase.
   [LenientSetter, Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   readonly attribute boolean fullscreen;
-  [BinaryName="fullscreen"]
+  [BinaryName="fullscreen", Deprecated="PrefixedFullscreenAPI"]
   readonly attribute boolean mozFullScreen;
   [LenientSetter, Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   readonly attribute boolean fullscreenEnabled;
-  [BinaryName="fullscreenEnabled"]
+  [BinaryName="fullscreenEnabled", Deprecated="PrefixedFullscreenAPI"]
   readonly attribute boolean mozFullScreenEnabled;
   [LenientSetter, Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   readonly attribute Element? fullscreenElement;
-  [BinaryName="fullscreenElement"]
+  [BinaryName="fullscreenElement", Deprecated="PrefixedFullscreenAPI"]
   readonly attribute Element? mozFullScreenElement;
 
   [Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   void exitFullscreen();
-  [BinaryName="exitFullscreen"]
+  [BinaryName="exitFullscreen", Deprecated="PrefixedFullscreenAPI"]
   void mozCancelFullScreen();
 
   // Events handlers
   [Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   attribute EventHandler onfullscreenchange;
   [Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   attribute EventHandler onfullscreenerror;
 };

--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -256,11 +256,11 @@ dictionary RequestFullscreenOptions {
 // https://fullscreen.spec.whatwg.org/#api
 partial interface Element {
   /**
    * The options parameter is non-standard. In Gecko, it can be:
    *  a RequestFullscreenOptions object
    */
   [Throws, UnsafeInPrerendering, Func="nsDocument::IsUnprefixedFullscreenEnabled"]
   void requestFullscreen(optional any options);
-  [Throws, UnsafeInPrerendering, BinaryName="requestFullscreen"]
+  [Throws, UnsafeInPrerendering, BinaryName="requestFullscreen", Deprecated="PrefixedFullscreenAPI"]
   void mozRequestFullScreen(optional any options);
 };