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!