--- a/mercurial/configitems.py	Fri Jun 30 03:45:42 2017 +0200
+++ b/mercurial/configitems.py	Fri Jun 30 03:45:43 2017 +0200
@@ -615,6 +615,9 @@
 coreconfigitem('web', 'descend',
     default=True,
 )
+coreconfigitem('web', 'description',
+    default="",
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )