--- a/mfbt/AlreadyAddRefed.h
+++ b/mfbt/AlreadyAddRefed.h
@@ -23,19 +23,20 @@ struct unused_t;
  * already_AddRefed cooperates with reference counting smart pointers to enable
  * you to assign in a pointer _without_ |AddRef|ing it.  You might want to use
  * this as a return type from a function that returns an already |AddRef|ed
  * pointer.
  *
  * TODO Move already_AddRefed to namespace mozilla.  This has not yet been done
  * because of the sheer number of usages of already_AddRefed.
  *
- * @deprecated This class is unnecessary now that RefPtr supports move
- *             construction.  New code should return a RefPtr instead of an
- *             already_AddRefed.
+ * @deprecated This class deprecated for use with RefPtr, now that RefPtr
+ *             supports move construction. New code should return a RefPtr
+ *             instead of an already_AddRefed.
+ *             Use with nsCOMPtr is *not* deprecated, and is still required.
  */
 template<class T>
 struct MOZ_MUST_USE_TYPE MOZ_NON_AUTOABLE already_AddRefed
 {
   /*
    * We want to allow returning nullptr from functions returning
    * already_AddRefed<T>, for simplicity.  But we also don't want to allow
    * returning raw T*, instead preferring creation of already_AddRefed<T> from