edit: No matter what one thinks about the privacy aspects of Signal: If its an official discussion group of this community it should be in the sidebar - just like the Discord group.
I therefore assume it's unofficial or maybe not even related to this comunity?
I like to imagine it as a fake Android CalDAV Client that doesn't subscribe to a CalDav Server, but instead to a directory that you define. The UI is also based on DAVx5. It doesn't store iCal-files, but Fossify Calendar allows export of events in iCal.
How does one "fork" a repo like this and then is proud about 100+ contributors he got?
I believe they know exactly what they are doing and just don't care.
Codium or VScode and Signal are not available as Browser Apps afaik.
And for Spotify - I rarely use that - but when I do it's nice to have the songs downloaded wich only exists in the Proton APP Version.
Xournal uses GTK - so that not working nicely would be a bummer.
I didn't know about Steam Deck using plasma - nice!