--- a/mercurial/configitems.py	Wed Oct 11 04:15:37 2017 +0200
+++ b/mercurial/configitems.py	Wed Oct 11 04:15:48 2017 +0200
@@ -742,6 +742,9 @@
 coreconfigitem('web', 'hidden',
     default=None,
 )
+coreconfigitem('web', 'labels',
+    default=list,
+)
 coreconfigitem('web', 'accesslog',
     default='-',
 )