diff -r afb442f58cbf -r 6c8e3c847977 mercurial/configitems.py
--- a/mercurial/configitems.py	Mon Jul 02 18:39:48 2018 -0700
+++ b/mercurial/configitems.py	Thu Jul 26 17:11:03 2018 -0700
@@ -931,6 +931,9 @@
     default=True,
     alias=[('format', 'aggressivemergedeltas')],
 )
+coreconfigitem('experimental', 'resolve.mark-check',
+    default=None,
+)
 coreconfigitem('server', 'bookmarks-pushkey-compat',
     default=True,
 )