[matthewmacleod]

This is not really true, for what it's worth. The latest releases of all browsers are fairly comparable; Chrome is a bit ahead, and Safari and Firefox mostly trade off against each other: https://caniuse.com/?compare=chrome+103,safari+15.5,firefox+...

[foepys]

Some of those are pretty major, while others are nice to have, and some others are privacy nightmares and Firefox not implementing them is deliberate, like the battery and gyroscope APIs.

Safari doesn't support CSS subgrids, AV1, Push API, HTTP/3, and regex lookbehind.

Except for Push API and video codecs, I see those as major flaws holding back the web.

Firefox can do better at some CSS functionality, with that I can agree.