--- a/mercurial/configitems.py	Fri Jun 30 03:45:36 2017 +0200
+++ b/mercurial/configitems.py	Fri Jun 30 03:45:37 2017 +0200
@@ -600,6 +600,9 @@
 coreconfigitem('web', 'cacerts',
     default=None,
 )
+coreconfigitem('web', 'certificate',
+    default=None,
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )