UADetector is a library to identify over 190 different desktop and mobile browsers and 130 other User-Agents like feed readers, email clients and multimedia players. In addition, even more than 400 robots like BingBot, Googlebot or Yahoo Bot can be identified.
Feedburner is detected as UNKNOWN. Reason seems to be a missing entry in uas.xml. This is the UA string: FeedBurner/1.0 (http://www.FeedBurner.com)