I had to dig around to see where they took the stand.

https://github.com/mozilla/standards-positions/issues/1213#i...

Mozilla makes great points. Even if the API is model agnostic, which it ought to be designed as from the very beginning to even be considered a spec, models can act vastly different.

Mozilla didn't say this but the user should at least be presented an option to choose which model (at least once) starting from day one, even if your browser only has one option available. That's assuming a universe where Google plans on actually being concerned about standards adoption.