--- a/mercurial/configitems.py	Mon Mar 19 16:49:53 2018 -0700
+++ b/mercurial/configitems.py	Wed Mar 14 15:25:06 2018 -0700
@@ -586,6 +586,9 @@
 coreconfigitem('experimental', 'web.api.http-v2',
     default=False,
 )
+coreconfigitem('experimental', 'web.api.debugreflect',
+    default=False,
+)
 coreconfigitem('experimental', 'xdiff',
     default=False,
 )