ref: 6e6beff85d3f2d71c4e1d92d1f2091d01c7d5c34 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>