If you want to tell an application where the RSS feed for the site is, include a <link> element in the <head> section of the HTML document with the following attributes:
1. rel = "alternate"
2. type = "application/rss+xml"
3. title = "RSS"
4. href = the address of the feed.
For example, this is the link element, which is included in the head section of every page in this blog, that helps you discover the feed.
<link rel="alternate" type="application/rss+xml" title="RSS" href="http://scripting.com/rss.xml" />
Note: This feature has been around since 2002, but I didn't have a current page that explains it. The original page is on the Radio UserLand site.