So it seems timeline.rss gives an empty document? I cannot reproduce this on a fresh repo:

$ fossil new test.fossil; fossil ui test.fossil

Go to localhost:8080/timeline.rss, got this feed:

<verbatim>
<?xml version="1.0"?>
<rss version="2.0">
  <channel>
    <title>Fossil source repository for:

    <description>Fossil source repository for:
    <pubDate>Tue, 20 Dec 2011 14:34:29 GMT</pubDate>
    <generator>Fossil version [132dbcedbc] 2011-12-16 22:00:37</generator>
    <item>
      <title>initial empty check-in</title>

      <description>initial empty check-in</description>
      <pubDate>Tue, 20 Dec 2011 14:34:19 GMT</pubDate>
      <dc:creator>dchest</dc:creator>

    </item>
  </channel>

</rss>
</verbatim>