For anyone working remotely like me, teams is a crucial piece of software (however bad it is). So as much as I like Firefox and legends that started it and religiously developed it over the years, bottom line, I can’t use it now.
Some maybe majority of blame falls on Mozilla, they let it stagnate and focus on cosmetic changes in last few years instead of focusing on improving core technology.
Teams has explicitly supported Firefox for a while now https://learn.microsoft.com/en-us/microsoftteams/teams-clien... but the problem is "there's always another site that doesn't work right". Firefox usage share got too low, so places just check Chrom* and Safari work with the new feature and ship (sometimes not even the latter, if they don't care about mobile as much).
I keep hearing it, but personally I’ve only come across one recently (a site was running some tracking bullshit that broke on FF). And there’s one feature broken on LinkedIn.
Webcompat used to be a lot more active (not sure if it's one of the things Mozilla has stopped actively engaging or not) but it was always a few big sites followed by an endless stream of "I'd never use that site, but that's precisely the kind of thing an average user wouldn't want to be troubleshooting" stuff. E.g. I remember seeing https://webcompat.com/issues/136422 and thinking "yeah, the hospitals I used to work at stopped testing in Firefox too - and the sites are already frustrating when they work as expected".
¯\_(ツ)_/¯
Citrix has always been shit, so is not surprising.
Except, instead of Chromium, Firefox, and instead of IE, Chromium.
It might have died with e10s but there was a firefox extension that let you embed IE in a tab on demand or for certain sites.
This doesn't particularly give people any confidence in your product if even the devs don't know how long they can hold the line. Why not fork Firefox like Zen?