We recently had some "FE devs" make a spiffy new SPA for some internal product. When I got to testing it on Firefox cause that's my main browser, I got a blank white page.

I asked them and they're like "yeah, it only works on chrome-based browsers". Or something to that effect. It's not like some CSS was wonky, or a bug somewhere... No, the default process of them building the SPA somehow yielded a completely non-functioning app for Firefox.