--- a/mercurial/exchangev2.py	Tue Oct 08 15:15:37 2019 -0700
+++ b/mercurial/exchangev2.py	Tue Oct 08 15:06:18 2019 -0700
@@ -219,7 +219,7 @@
                     vfs = repo.svfs
                 else:
                     raise error.Abort(
-                        _(b'invalid location for raw file data: ' b'%s')
+                        _(b'invalid location for raw file data: %s')
                         % filemeta[b'location']
                     )