I'm concerned about the new changes that disallow, e.g. aria-label on HTML elements without a supported role.

As advice to authors, it sounds great. It's probably not ever correct to put aria-label on a <div> with no tabindex or role.

But I'm concerned about browsers implementing this and enforcing it. Browsers can't just make such a large breaking change like this without carefully understanding the ramifications. We might have to add use counters to see how prevalent this error is, and put a message in the JS Console for 6 months to give developers warning.

And, we don't even know for sure if there aren't more obscure but valid use-cases that would be broken by this. While screen readers largely ignore such names, are we sure that all AT does? What about automated testing tools?

I think we have two possible courses of action:

1. Flag this as a major change and try to get all browsers onboard with making it slowly and carefully so as not to break anything that users or developers are relying on

2. Or, maybe we need to introduce something new like an ARIA strict mode, that would let developers opt-in to having this enforced.