You mean Firefox that refuses to support web standards for encoded video streams for ideological reasons?

Wasn't aware of that, can you send a link explaining?

For a while Netflix didn't support 1080p on browsers other than Edge on Windows or Safari on Mac. This has changed somewhat but they still reserve their resolution content for their "blessed" OS/browser combinations

https://help.netflix.com/en/node/30081

It's not just Netflix. It is also FaceTime calls for Firefox. This is the reason why Netflix limits Firefox.

Here's the discussion of that: https://news.ycombinator.com/item?id=27432001