Try https://meet.google.com in any browser other than Chrome and you'll get a message saying your browser isn't supported.

If you setup Firefox to use a newer version of Chrome user agent, the page will at least load. Seems like they are using user agent instead of feature detection to limit usage.

Inbox when first launched was only available on Chrome and blocked other browsers via user-agent. However, if you were using Firefox and changed the user-agent to Chrome, everything worked fine.

Well the missing functionality comes and go, hard to keep track. One current that I know of is Google Maps (the Earth mode).

Also virtually every tech demo they did over the years. One might argue that makes sense, but it really doesn't. Change user agent and it works (it's standards after all, and half the browsers on market are Chromium based anyway).