Hard to say "fork on gitlab" when our gitlab instance effectively rips outsiders from most uses of gitlab.
https://gitlab.inria.fr/dldb/discretelogdb/-/blob/master/index.html#L91 is quite misleading.
For outsiders, to get an account on Inria gitlab, the long-winded path is here ; and to get from that to being able to fork a project, it's even harder. I'm not even sure it's in fact possible for outsiders to own a project in the first place.