--- a/mercurial/configitems.py	Wed Oct 11 04:57:54 2017 +0200
+++ b/mercurial/configitems.py	Wed Oct 11 05:18:20 2017 +0200
@@ -212,6 +212,9 @@
 coreconfigitem('experimental', 'allowdivergence',
     default=False,
 )
+coreconfigitem('experimental', 'archivemetatemplate',
+    default=dynamicdefault,
+)
 coreconfigitem('experimental', 'bundle-phases',
     default=False,
 )