I agree with Warner here.
This is the reason I leave $OpenBSD$ (please please don't blame me :))
in some files. 

> In message <20010120112339.E399@dr-evil.shagadelic.org> Jason R Thorpe writes:
> : If it were a driver originally obtained from FreeBSD, that'd be one
> : thing, but a list of device IDs, seems totally pointless.
> 
> I wouldn't call it totally pointless.  It lets me know where in the
> stream of both sets of versions each one is sync to.  I can easily
> then do a cvs diff -u -r A -r B based on what's in the tag line.
> 
> It helps keep both files in sync with each other.  And also helps
> identify the devices added to one group but not the other so that I
> can submit patches the the appropriate drivers.
--
soda