ref: c1d40df49550393f3afe53fb6e6d500dfa8eb7a8
dir: /sys/src/cmd/hg/templates/rss/error.tmpl/
{header} <title>Error</title> <description>Error</description> <item> <title>Error</title> <description>{error|escape}</description> <guid>http://mercurial.selenic.com/#error</guid> </item> </channel> </rss>