As I understand it, this isn't really a super strict thing, it's more about sticking to the spirit of the challenge. As long as the rules themselves can fit on one page (even if it's front and back), then it doesn't really matter how many different versions of that one page you have, that's just being nice to people who speak different languages. Character sheets/cards are specifically called out as something you can use a separate file for, since it's about the rules being able to fit on one page, not everything you might need to play the game. That'd be like requiring you to include dice on your one page as well, which would be a little silly.