diff --git a/CLOBBER b/CLOBBER
index f0f6c2819bc5..b02b8fc90d36 100644
--- a/CLOBBER
+++ b/CLOBBER
@@ -18,4 +18,4 @@
 # Modifying this file will now automatically clobber the buildbot machines \o/
 #
 
-Another Windows WebIDL clobber needed due to bug 674741
+Bug 928390 requires a clobber because of bug 939416.