diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
index 56674fd6dabc00a6614e31c8e23c891fb6c68099_bWVyY3VyaWFsL3N1YnJlcG8ucHk=..0ae07173881d637d688f402ce45315ecbd2ff88d_bWVyY3VyaWFsL3N1YnJlcG8ucHk= 100644
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -607,6 +607,7 @@
             v = r.ui.config(s, k)
             if v:
                 self.ui.setconfig(s, k, v, 'subrepo')
+        # internal config: ui._usedassubrepo
         self.ui.setconfig('ui', '_usedassubrepo', 'True', 'subrepo')
         self._initrepo(r, state[0], create)