diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index a31fb66c7c26..106268b67a69 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -615,7 +615,7 @@ if CONFIG['MOZ_B2G_BT']:
         'BluetoothStatusChangedEvent.webidl',
     ]
 
-if CONFIG['MOZ_BUILD_APP'] in ['browser', 'xulrunner']:
+if CONFIG['MOZ_BUILD_APP'] == 'browser':
     WEBIDL_FILES += [
         'BrowserFeedWriter.webidl',
     ]