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)
We too have some slop issues; this past day this site and the sister site had to answer about 2.5 million requests (not counting Gemini Protocol) and it's slowing things down for everybody