I'd make a smart-assed comment but... (thanks snap!)
I'd make a smart-assed comment here... but, courtesy of snap, I had my (snap-based) copy of firefox lose it's ability to save files for a bit just last night! I had a swap-storm (from running entirely too much stuff), firefox then couldn't save. (This doesn't make sense but...) snap restricts where firefox can save files, so it uses "xdg-portal" to save outside that area... (to me it doesn't make sense, it's jumping through a hoop to just be able to save wherever anyway.. so why have the restriction to begin with? Anyway...) I suppose something timed out and it decided xdg-portal was gone... I don't know, whatever happened saves didn't work for a good while, then later on they started working again.