diff -r b82c6dd15f5d -r 704095e27c5c mercurial/ui.py
--- a/mercurial/ui.py	Sun Feb 04 12:00:17 2018 +0100
+++ b/mercurial/ui.py	Sun Feb 04 15:41:37 2018 +0530
@@ -45,7 +45,7 @@
                      if not c.isalnum())
 
 # The config knobs that will be altered (if unset) by ui.tweakdefaults.
-tweakrc = """
+tweakrc = b"""
 [ui]
 # The rollback command is dangerous. As a rule, don't use it.
 rollback = False