Seems to work fine if you change the FF user agent to Edge.
Does not run under Linux regardless of user agent or browser, while running perfectly in Edge on both Windows and macOS. Very confusing...
It doesn't even run in Epiphany (Gnome Web)! Which is the closest thing to Safari.
Took them way too long to figure out visibility is needed to close the loop on map data. That said I just do not understand what is in it that prevents it from working on Firefox.