Okay, this is actually in libgnome-desktop

discussed with mark on irc, there could be issue of
whether changes made to the categories field should be 
dynamically reflected.waiting for mark to be back on line.

Mark: I'm unclear why this is high priority?

There is no good way to do a GUI for this currently, because what we
really need is a list of all known keywords (or descriptions of what
they do), otherwise it will be an ugly comma separated list or something.

It also breaks UI and string freeze.

I think leaving this as a manual edit is fine for now.

Yeah, it's fine to leave this off for now.  The vfolder proposal has a
list of allowed keywords, but those need to be better published and
then we need some nicer UI for this.  For file style editting of menus
we don't really need/want this since there the actual vfolder nature
is hidden from the user.  What we really want is to have a menu editting
"view" for nautilus that would handle correctly editting the vfolder
file including all the categories and all that fun kind of stuff.

Closing as invalid, as this shouldn't be shown to the user, and no one
seems to really want it anyways.