--- a/mercurial/configitems.py	Fri Jun 30 03:45:49 2017 +0200
+++ b/mercurial/configitems.py	Fri Jun 30 03:45:50 2017 +0200
@@ -634,6 +634,9 @@
 coreconfigitem('web', 'prefix',
     default='',
 )
+coreconfigitem('web', 'refreshinterval',
+    default=20,
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )