diff -r 36200dc6b3bd -r 0ff44e06275d mercurial/localrepo.py
--- a/mercurial/localrepo.py	Thu May 29 14:59:22 2014 -0700
+++ b/mercurial/localrepo.py	Tue May 27 15:43:09 2014 -0700
@@ -180,7 +180,8 @@
     requirements = ['revlogv1']
     filtername = None
 
-    bundle2caps = {'HG2X': ()}
+    bundle2caps = {'HG2X': (),
+                   'b2x:listkeys': ()}
 
     # a list of (ui, featureset) functions.
     # only functions defined in module of enabled extensions are invoked