--- a/hgext3rd/pullbundle.py	Tue Aug 06 11:30:45 2019 +0200
+++ b/hgext3rd/pullbundle.py	Tue Aug 06 11:32:01 2019 +0200
@@ -436,7 +436,7 @@
     # opening too many file will not work.
 
     def data():
-        with open(bundlepath, 'rb') as fd:
+        with open(bundlepath, r'rb') as fd:
             for chunk in util.filechunkiter(fd):
                 yield chunk
     return data()