The author has marked this style as obsolete.
Updated again. They've changed it again.
I've been using Gmail - hide bold spam count by Frank (DesertFox) for a long time, but recently there was code updates inside GMail (http://gmailblog.blogspot.com/2007/10/code-changes-to-prepare-gmail-for.html) and with them all class names were changed (at least for "Spam (XXX)" link), I decided not to wait for an update for the old style and updated it myself.