ref: f1c3a1a6a89ba8a801e10ef3e75fe0dc7a2a9149 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>