Perhaps you didn’t see the (deleted) comment I was responding to, but they were speaking from the position of a web developer, not from the perspective of a normal user:
I’m a software engineer, and when I build web apps, Firefox now stands in the way of me being able to use new standard features (without polyfills). Meaning, if I want to support the 2-5% of users that may use Firefox, I have to explicitly go out of my way to either make my site less efficient for everyone, or build a special version just for Frefox because it’s so behind, like we used to with IE, making Firefox the new IE (except nobody is really using it). And of course, you can only polyfill so much. Some things are utterly impossible, such as the various PWA features that Mozilla refuses to support, or many new CSS features coming out.
“What major standard features is Firefox missing these days?”
This was your question, nowhere did you say anything about web API’s. You stupid or just forget which comment I was responding to?
Sure FF has extensions that “kinda do the same thing” except they’re shit and bloat the browser beyond what it already is compared to Vivaldi.
Perhaps you didn’t see the (deleted) comment I was responding to, but they were speaking from the position of a web developer, not from the perspective of a normal user: