IPv6
Not rly a bug, but you may considering to you give ipv6 a chance.

System: Mozilla/5.0 (Windows NT 10.0
Thanks! My understanding is Firebase Hosting (where I host my web app) supports IPv4 and IPv6 already and you're simply seeing the IPv4 address. Not sure if I need to do something to force IPv6 ... are you saying this shows as only supporting IPv4?
Unfortunately, I have no experience with Firebase hosting. But an IPv6 query shows that there are no AAAA entries made for simpl.fyi: https://ready.chair6.net/?url=simpl.fyi
In the documentation of Google Firebase I didn't find anything about IPv6 either. Only found an older Google Groups entry about the topic: https://groups.google.com/g/firebase-talk/c/eE6kAqDApU8
The IPv4 addresses seem to be up to date, but I can't say if they are the current IPv6 ones.
Can you open a ticket at the Firebase Support?