[FormularSumo]

Did you try opening the page? Each feature says which spec it's part of (e.g. "W3C Draft", "W3C Candidate") with a link to it. It also shows which browser implemented a feature first. Often it's Chrome, but sometimes it's Firefox, Opera, or even desktop Safari!

Likewise, you can click on the Chrome icon to change comparison browser. Here's a list of features implemented in Firefox on Android but not in Safari on iOS (and therefore, not in Firefox on iOS either):

https://ios404.com/?browsers=andff

Fwiw, I've been a Firefox user for about 9 years. I would love to see Firefox be able to ship their engine on iOS. The main reason Firefox haven't implemented as many features as Chrome is that they lack the resources to. Anti-competitive behaviour has hurt them a lot, and being forced to use a sub-par, undifferentiated browser engine on iOS - the world's most valuable and influential OS, has played a big part in this.