[kh99]

I believe those refer to tags and attributes in the rss feed xml, which is described here: http://validator.w3.org/feed/docs/rss2.html

Also, looking at the vbulletin code that reads an rss feed, id is the same as guid (which is just a string that's unique to that item), date is the same as pubDate (the date it was published), and enclosure:href is the url attribute of the enclosure tag.

There's also a couple others you didn't list above, title and author. Actually, I think you may be able to use feed:tag or feed:tag:attribute to access the value of any tag or attribute from the rss feed xml.

I hope this makes sense - I'm not an expert on the subject, I'm piecing it together by looking at the rss spec and the vb code.