Top of this list used to be particular versions of Ubuntu
Summary: GNU/Linux "market share" in Steam grew by a quarter this past year, boosted by SteamOS perhaps, but watch the trends in distributions; even the Ubuntu-based distros aren't near the top (and SteamOS moved from Debian to Arch, so expect Ubuntu to stagnate further)
"As David explains, the Codes of Conduct should work the other way around to regulate the poor behavior of corporations who have been far too close to the Debian Suicide Cluster."