Hi, LLIโ , I can guide you through sorting this out, if you like.
The PWA runs in any browser, but you have to make concessions that ( just like everyone else in the world ๐ฉ) they do not properly test with any other browser engine than chromium, so functionality is ... slow ... to stay properly good.
Ostensibly, though, if you install the PWA Add-on / Extension (soon to be subsumed into the mainline code - or a version / mozilla version therein) then you can make PWAs for literally anything, really. I have mine running 3 different tenancies, currently, via the Multi-Account Containers. ;)
Find me on my LinkedIn vanity of eliot dot cole if you need more. ๐
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Relatedly, though ... It would be nice for BASE application functionality to be enabled in the PWA, though ... because if we are able to (for example) add a background image to our meetings (and for it to stick) then we should be able to do it in the Web App without premium add-ons.