And MDN is owned by Mozilla :-) Between the two of them, I think we've got ourselves covered.
Yes MDN is excellent
It’s more than web.dev simply being owned by Google, at times the site feels like content marketing for Chrome and not just a resource to learn about web development. I’ve seen them post multiple articles about the latest Chrome-only updates, while I’ve never seen MDN promote content that only focuses on Firefox. Not to say MDN has never done that, but at least to me, web.dev has a definite Chrome bent that you wouldn’t expect from the way the site initially presents itself.
> I’ve never seen MDN promote content that only focuses on Firefox
Fair point but this is also directly labeled as stuff. Most of the Chrome-only stuff on web.dev barely tells you that. It is at most a footnote that this isn't available in most browsers and that the other browsers may actually be opposed to implementing the Chrome proposal.