MDN is the current best in class. I don't 100% agree with everything they say, but I don't agree with the direction HTML 5 has been dragging us so...

In a lot of ways HTML 5 is more like HTML 3 than anyone wants to admit. As someone who embraced 4 Strct, it's a bit disheartening to see 20+ years of progress undone and genuine planned improvements (like reducing the number of tags and attributes) shelved.

But MDN follows the actual specifications, and I really can't poo-poo on that too hard. Certainly head and shoulders above ignorant dirtbag scam artist BS like W3Schools.