This game would be played on GitHub. One person would make a list of some food items, one would make list of some shopping articles, one would make a list of restaurants, and one would make a list of places worth sightseeing. These would be uploaded as a repository in GitHub. And then we shall collaborate.
It’s not going to be illegal and the repositories are going to be public. But instead of serious coding work, it would be playing - like kids do. Do you get what I mean ? Codeberg allows that ??
Yes, why wouldn’t it?
First, read the actual ToS. That will spell it out.
Second, even if they kick you off the platform, what’s the loss? Git doesn’t depend on a single server by design. If you have to switch to a different provider, all you have to do is set up an empty repository on the new platform, change the local repository’s remote, and push. If the goal is to learn how to use git, then managing the remotes should be a part of it.
They insist on license. But what license could there possibly be for a game ?