Slack isn't feature complete in their webapp if they even still have it. vscode.dev is new, the app existed for a long time. In practice, its the reverse; it allows you to turn an app into a website and add yet another supported platform.
This is something I think many HN'ers don't understand. For a good amount of modern web functionality, being supported in Firefox is less a matter of "do testing in firefox and make sure things work there" as much as it is "have a very popular product and good marketing team so that you can convince the firefox team to whitelist your domain in their internal maps of `what cool things should X domain be allowed to do`". People see that Slack works in Firefox, but Joe's Voice Calls.Com doesn't, and blame Joe for not supporting firefox. In reality it's firefox that doesn't support Joe.
You misunderstand, you have the situation exactly backwards. The problem isn't that Firefox doesn't support these APIs, it does support them and the problem isn't that they are limited to specific domains, they aren't. The problem is that the Slack code is `if isChrome() { enableCalls() }`. Mozilla has to spoof the user-agent to bypass this check. Joe's Voice Calls.com will just do no conditional or do feature-detection rather than user-agent checks and everything will work fine.
The exception is the list of domains that allow auto-play video with sound by default (like YouTube) but I think there are very few instances of this.
Ah, indeed I misunderstood. Though to be fair, at $DAY_JOB we had to do exactly the process I described above to access some API (not auto-play) without a litany of obnoxious prompts. If anyone at a smaller company tried to do what we were doing, they'd be 100% unable to provide a usable experience for Firefox users.
