Given a gitlab project/group access token, how do I find out the name of the token and from which group/project it came from?
You can use the user api such as:
wget --header "PRIVATE-TOKEN: <TOKEN>" https://www.gitlab.com/api/v4/user
Though this API you'll get the user that token is attached to. If the token is attached to a group or a project, you'll see the type and project/group ID in the results.