ref: 4308f6e7e6586e3a27aa46c4d54c434b8533b16d 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>