diff -r d43340bec0f5 -r cf08aaaea7f0 mercurial/hgweb/hgwebdir_mod.py
--- a/mercurial/hgweb/hgwebdir_mod.py	Sat Sep 16 11:48:05 2017 -0400
+++ b/mercurial/hgweb/hgwebdir_mod.py	Fri Sep 15 19:21:08 2017 +0200
@@ -491,7 +491,7 @@
             else:
                 yield config('web', 'motd', '')
 
-        def config(section, name, default=None, untrusted=True):
+        def config(section, name, default=uimod._unset, untrusted=True):
             return self.ui.config(section, name, default, untrusted)
 
         self.updatereqenv(req.env)