diff -r 127b59787fd5 -r cff70549a959 mercurial/error.py
--- a/mercurial/error.py	Wed Sep 23 11:33:30 2015 -0700
+++ b/mercurial/error.py	Wed Sep 23 11:44:52 2015 -0700
@@ -141,7 +141,7 @@
 class BundleValueError(ValueError):
     """error raised when bundle2 cannot be processed"""
 
-class UnsupportedPartError(BundleValueError):
+class BundleUnknownFeatureError(BundleValueError):
     def __init__(self, parttype=None, params=()):
         self.parttype = parttype
         self.params = params