--- a/mercurial/templatekw.py	Thu Apr 06 19:24:04 2017 +0200
+++ b/mercurial/templatekw.py	Sun Apr 09 00:10:54 2017 -0400
@@ -432,7 +432,8 @@
 @templatekeyword('latesttag')
 def showlatesttag(**args):
     """List of strings. The global tags on the most recent globally
-    tagged ancestor of this changeset.
+    tagged ancestor of this changeset.  If no such tags exist, the list
+    consists of the single string "null".
     """
     return showlatesttags(None, **args)