By "doing many different things", I meant that everything disagrees on what should be config and what should be data. People will disagree with any division you pick for something with as varied types of data as a web browser. And some of them will be right, and for good reasons, which means you'll have to sign up for repeated migrations across different versions.

I'm not saying it's a bad idea to try to follow xdg, just that it's a complex and ongoing thing. It's a good example of the "Just do X!" fallacy.