--- a/mercurial/configitems.py	Wed Oct 11 04:14:14 2017 +0200
+++ b/mercurial/configitems.py	Wed Oct 11 04:14:33 2017 +0200
@@ -727,6 +727,9 @@
 coreconfigitem('web', 'allowzip',
     default=None,
 )
+coreconfigitem('web', 'cache',
+    default=True,
+)
 coreconfigitem('web', 'accesslog',
     default='-',
 )