There is an option at the bottom of account preferences to set your platform to SteamOS + Linux
Despite this setting being checked, the desktop Steam Client Store page, the Steam website, and the Store in Steam Big Picture mode all still show non-Linux games.
Nothing extracted yet.
I don't plan on purchasing games if they don't support my OS of choice, so I don't want to see them in the store, but I'd like to still be able to play my existing ones from the couch via streaming. So, give us the option to manually toggle each of the platforms on our list of playable platforms, rather than just letting us choose between showing all games and showing playable ones in the store.