ref: 0e96fd0197e0ce8d4e69cb1e0dc96dcfb4bb3a1e dir: /sys/lib/python/mercurial/templates/rss/header.tmpl/
<?xml version="1.0" encoding="{encoding}"?> <rss version="2.0"> <channel> <link>{urlbase}{url}</link> <language>en-us</language>