--- a/mercurial/configitems.py	Fri Jun 30 03:42:22 2017 +0200
+++ b/mercurial/configitems.py	Fri Jun 30 03:42:23 2017 +0200
@@ -113,6 +113,9 @@
 coreconfigitem('format', 'dotencode',
     default=True,
 )
+coreconfigitem('format', 'generaldelta',
+    default=False,
+)
 coreconfigitem('hostsecurity', 'ciphers',
     default=None,
 )