ref: 3a4a6d2dd2a3dc812ad31a2c1ee663a7e7ed0bfa 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>