Maybe this is an old change, and everybody else knew about it, but I discovered just now that if you click the Steam Deck compatibility “Learn more” button then it also have tabs for SteamOS, Steam Machine and Steam Frame.
Didn’t just happen but it’s a recent (and welcome) change, just a couple months or so really… The Frame was just added in the last couple weeks but Machine and OS were both added around when Machine released.
Very useful for Linux gamers in general!
Just keep in mind that Linux compatible =/= Steam Deck compatible. For example a title may not perform well on Steam Deck, but run just fine on Linux with beefier hardware.
Iirc, ProtonDB has separate sections for steamdeck and linux with Proton in general. Highly worth checking out if buying a new game on either system.