Ah, thanks a lot, and sorry for the stupid question
I have already tried checkout, however I was a little bit confused at first, because the log showed no newer revisions than mine (so I thought the checkout of an older version had no effect). This behaves not like SVN, which makes sense since the newer revisions are only part of another, decentral repository.
In fact, I also tried git describe, but as you say, no names appeared.