diff -r aca0954d3739 -r e83f89d3b1f7 mercurial/help/templates.txt
--- a/mercurial/help/templates.txt	Sat Sep 17 17:02:56 2016 +1000
+++ b/mercurial/help/templates.txt	Fri Sep 23 08:15:05 2016 +0000
@@ -95,6 +95,10 @@
 
    $ hg log -r 0 --template "files: {join(files, ', ')}\n"
 
+- Join the list of files ending with ".py" with a ", "::
+
+   $ hg log -r 0 --template "pythonfiles: {join(files('**.py'), ', ')}\n"
+
 - Separate non-empty arguments by a " "::
 
    $ hg log -r 0 --template "{separate(' ', node, bookmarks, tags}\n"