diff -r 3a0f322af192 -r 443029011990 mercurial/encoding.py
--- a/mercurial/encoding.py	Wed Jul 04 14:19:13 2018 +0200
+++ b/mercurial/encoding.py	Sun Jul 01 23:36:53 2018 +0900
@@ -72,6 +72,11 @@
     '646': lambda: 'ascii',
     'ANSI_X3.4-1968': lambda: 'ascii',
 }
+# cp65001 is a Windows variant of utf-8, which isn't supported on Python 2.
+# No idea if it should be rewritten to the canonical name 'utf-8' on Python 3.
+# https://bugs.python.org/issue13216
+if pycompat.iswindows and not pycompat.ispy3:
+    _encodingfixers['cp65001'] = lambda: 'utf-8'
 
 try:
     encoding = environ.get("HGENCODING")