When I wrote the IssueTrackerProduct that was very early in the development of the TAL implementation by Evan Simpson.
Back then the "omit-tag" tag to TAL didn't exist. Or maybe it was about to but the version I was using didn't.
This solves some problems with TAL that I've had.
Plus, you can use it nicely with metal tags so that you can get rid of those little pointless metal:fill-slot tags.