Fixes broken FF4 functionality Rated 5 out of 5 stars
This plugin does the job. I think it's better than the other one, "RSS Icon". This one displays the RSS icon to the right side of the bookmark star (=good), and it doesn't flicker when a site with RSS feed loads.
The only issue I've found is that when navigating using the Back button and the site loads from Firefox cache, the RSS icon isn't displayed (even if the site has an RSS feed).