--- a/mercurial/wireproto.py	Fri Aug 05 13:53:45 2016 +0200
+++ b/mercurial/wireproto.py	Thu Mar 02 03:23:18 2017 +0100
@@ -736,7 +736,7 @@
     depending on the request. e.g. you could advertise URLs for the closest
     data center given the client's IP address.
     """
-    return repo.opener.tryread('clonebundles.manifest')
+    return repo.vfs.tryread('clonebundles.manifest')
 
 wireprotocaps = ['lookup', 'changegroupsubset', 'branchmap', 'pushkey',
                  'known', 'getbundle', 'unbundlehash', 'batch']