--- a/mercurial/configitems.py	Sun Oct 08 21:41:22 2017 +0200
+++ b/mercurial/configitems.py	Sun Oct 08 21:41:37 2017 +0200
@@ -134,6 +134,9 @@
 coreconfigitem('devel', 'disableloaddefaultcerts',
     default=False,
 )
+coreconfigitem('devel', 'empty-changegroup',
+    default=False,
+)
 coreconfigitem('devel', 'legacy.exchange',
     default=list,
 )