ref: 2e94406e7f66b0c5f4e2b1d5c2158a37e8677724 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>