ref: cdaa7b899f874f4e0e6c8a04dcf6a5a3a7dfafdf dir: /sys/src/cmd/hg/templates/rss/header.tmpl/
<?xml version="1.0" encoding="{encoding}"?> <rss version="2.0"> <channel> <link>{urlbase}{url}</link> <language>en-us</language>