diff -r de8e3681c402 -r 46fa46608ca5 mercurial/templatekw.py
--- a/mercurial/templatekw.py	Sat Jun 24 13:39:20 2017 -0700
+++ b/mercurial/templatekw.py	Sat Jun 24 14:52:15 2017 -0700
@@ -557,10 +557,12 @@
 
     namespaces = util.sortdict()
     colornames = {}
+    builtins = {}
 
     for k, ns in repo.names.iteritems():
         namespaces[k] = showlist('name', ns.names(repo, ctx.node()), args)
         colornames[k] = ns.colorname
+        builtins[k] = ns.builtin
 
     f = _showlist('namespace', list(namespaces), args)
 
@@ -568,6 +570,7 @@
         return {
             'namespace': ns,
             'names': namespaces[ns],
+            'builtin': builtins[ns],
             'colorname': colornames[ns],
         }