to give you a quick explanation about what that file actually is, it basically is the key needed to decrypt that specific disc with its specific game on it. if somebody has a disc with the same game, game version and game region it will work, otherwise it will not since the ISO on it is a different one, nintendo uses a different key for each ISO, the easiest way to check that is by the hashes automatically created by wudump.for example, would the game.key from my legit copy of mario maker still work with someone else's copy of mario maker, or a copy of mario maker randomly downloaded from somewhere? (sorry for all the questions, just trying to better understand how all this key stuff works. last one i think! )