Doesn't work for me. All I see in Firefox (on desktop) is a blurry earth animation which you can zoom but which does nothing. There are some errors in the console and that's about it. There might be some text or something in the lower left corner but that is blurry too.
Similar for me. Can enter location, but the tab freezes after i hit "go". Looking at the taskmanager, there is a FF content process using an entire core. Dev tools are kind of unresponsive and the process keeps running for a while even after closing the tab (the first 3 even til i killed them via taskmanager). Confusingly, it runs fine on another PC with same ff version + addon setup. So yeah, I'm confused and out of ideas :(
There should be a Firefox location permission prompt, which you can allow or decline to continue. If not, perhaps an extension is blocking the geolocation API?
It's not required. Perhaps Firefox's implementation of privacy blocking breaks the behavior of the API, which has a standard way of denying location information. Or maybe you're also blocking the IP geolocation service that I use as a fallback.
Just following up, I tested in Firefox with strict privacy settings and location disabled, and it works for me with the IP geolocation fallback. If IP geolocation fails I have a further fallback to enter your street address. So something else must be broken.