Comment by mikepurvis
9 days ago
GitLab has been talking about federation at least between instances of itself for 8+ years: https://gitlab.com/groups/gitlab-org/-/epics/16514
Once the protocols are in place, one hopes that other forges could participate as well, though the history of the internet is littered with instances where federation APIs just became spam firehoses (see especially pingback/trackback on blog platforms).
Gitlab has also indicated not to be interested as a company to develop this themself, and esp. not given all the other demands they get from their customer base. The epic you refer to had been closed for this reason, but was later reopened for the sake of the community. For there to be federation support in self-hosted Gitlab instances, a further community effort is needed, and right now AFAIK no one is actively working on any ActivityPub related user stories.