Earlier quoted context omitted.
Note how it doesn't list which of these are Chrome-only non-standard APIs that Firefox doesn't support either. Oh wait. You don't care about small details like that. None of these Chrome shilling websites do.
Hi! Creator here (of iOS404) - you can filter level of standard and compare to FF Android (or compare to Safari Desktop, or any mix) instead if you'd like.
There are 34 features listed (IIRC it did contain a bunch of Chrome-only crap once upon the time, hence my harsh reaction). All of them enabled by default. If we limit this only to actual, you know, standards, and not "scribbled on a napkin, awaits review", we get a grand total of 9 (yes, nine). And even there many are not "not implemented" but "missing some features (sometimes big, sometimes small and irrelevant)".