mercurial/configitems.py

--- a/mercurial/configitems.py	Fri Jun 30 03:45:37 2017 +0200
+++ b/mercurial/configitems.py	Fri Jun 30 03:45:38 2017 +0200
@@ -603,6 +603,9 @@
 coreconfigitem('web', 'certificate',
     default=None,
 )
+coreconfigitem('web', 'collapse',
+    default=False,
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )