This is the answer. Look up the Facebook Pixel and Like Button. Putting them on a site lets Meta track your activity across the web, even when you’re logged out or don’t have an account. I’m sure Twitter, Reddit, et al. are doing the same by now.

Okay the extension I have is called “Sound Input & Output Device Chooser.” I think that if you install this and the Other extension above your problem will be solved.

I use Pop and have a Gnome extension that helps with this. I’m not at home now and I can’t remember the name but I can report back later.

Doing a quick search on this gave me “Application Volume Mixer” but I don’t think this is the exact extension I have.