i know there are values, but the value can change per checkin:

i.e.:
checkin 53739292 tag foo=bar
checkin 39203748 tag foo=bar2

i think it could be useful to have a comment which explains a tag.
this comment could also be displayed in the taglist (http://www.fossil-scm.org/index.html/taglist)

anonymous added on 2010-03-19 14:32:06:
this could be also useful for branches...

martin.weber added on 2011-09-07 13:21:24 UTC:
This would be helpful for everything, wouldn't it? Not only to document something, but also to discuss things; just like we have the audit trail in the ticket system where you can append remarks, that would be nice to have (imho) for anything. Right now in fossil development itself we bring things up on the mailing list -- not everyone has a mailing list though, so discussing things "in place" would/could be a nice fossil feature.

viriketo added on 2011-09-07 13:41:06 UTC:
I usually explain the meaning of the branch at two moments: creation checkin, and merge into parent checkin (as the purpose may have changed among the two).