Quote My last three data points are:

25/09/15 - 1521 games

09/10/15 - 1555 games

16/10/15 - 1535 games

@gamingonlinux It is because the game requires Java. When the new launcher comes out this should be resolved! — StarMade (@star_made) October 17, 2015

Article taken from GamingOnLinux.com.

This is quite interesting, it seems Valve are actually doing some more curating on their store now ahead of the SteamOS launch.A user on reddit posted about ~35 titles having their SteamOS icons vanish. To quote the user:I've checked myself, and I can see that Ticket to Ride, Anodyne, Lume, WAKFU, Starbound, Evoland, Oniken, StarMade and Defender's Quest: Valley of the Forgotten have had their icons removed. I'm not sure what other games have seen the change, as that's a lot of games to go through to find out.I spoke with the developer of StarMade who said this:I spoke with other developers, but some are still looking into why, and some asked me not to mention them here.It makes perfect sense, you wouldn't want a new SteamOS user to find out a game that advertised SteamOS support needed some outside launcher/installer for something like adobe air, or flash or anything else that needs a fair bit of manual interaction not directly possible in the SteamOS interface.I guess the minor issue for us here, is that people on desktop Linux can't get these games on Steam now, but they do still show in my library, and are installable. It's probably a good thing though, as it means any game with a SteamOS icon should install on desktop Linux without the hassle of hunting down extra's. I wonder how far this will go though? Will they remove all games that have a launcher that doesn't work in fullscreen? It's going to be interesting to see what happens.They aren't removing the games from your library, so let's not go ringing alarm bells. However, I did say a long time ago I was worried about SteamOS becoming separated from Linux and people thought Valve wouldn't do it, I thought they wouldn't, but this could be the start for all we know.