I - the issuer of this commit - have asked to get removed from the GitLab group like three times now. The first time was a year ago. As you can read this message, I am still able to commit to this group's projects.
In my opinion, programmers are allowed to program a mild prank when they want to leave a GitLab group they cannot leave themselves, and are ignored for such a long time.
Therefore, I have added this file in a new branch in every project I can access in the GitLab group (and subgroups). I also opened a merge request for this branch in every project.
This causes no harm and hopefully has the desired effect: I finally get removed from the group, and its admins take a little more care about who actually is a member. Imagine what else I could have programmed :)
In case you don't want to delete the merge requests and branches by hand,
you can download the script from LaumiH's repo and run it using python3 de-prank.py -group <group> -name <name>.
It is well documented so that non-Python speaking people comprehend that it really does nothing apart from deleting the merge requests and branches.