diff --git a/mozilla/modules/libpref/public/MANIFEST b/mozilla/modules/libpref/public/MANIFEST
index 962c4875c45..a9ee2f3ee15 100644
--- a/mozilla/modules/libpref/public/MANIFEST
+++ b/mozilla/modules/libpref/public/MANIFEST
@@ -2,6 +2,7 @@
 # This is a list of local files which get copied to the mozilla:dist directory
 #
 
+#[installed by xpidl] nsIPref.h
+
 prefapi.h
 prefldap.h
-nsIPref.h