... For those who like to put random things in the Data folder, there's WT. ....

I am actually against this approach, which is why WT was created to break this vicious cycle. That's why I implemented automatic updates so that everyone has a SINGLE version with the same set of resources.
And when I create a built-in feature to synchronize settings and rules with the opponent, i.e., display your settings (and rule items) next to the opponent's settings, and highlight in red where they don't match, and where they do match, so you can start the game, I plan to check the correctness of both players' resources against a reference version, so that no one puts anything extra anywhere.