Me? Oh, Flatpak Linux, of course.

They include a note about that on the page

Flatpak is NOT a distro, but that’s what Steam reports when it’s running on Flatpak, and Flatpak being distro independent we report it as a separate environment, if that makes sense. Feel free to ignore it if you wish.

Doesn’t steam run as a flatpak on bazzite?

No, it actually does not run the flatpak version.

Steam is essentially treated as part of the core Bazzite OS.

Bazzite runs more or less the latest Fedora version of Steam, and then has a ton of custom scripts, as well as accomoanying core-Fedora library utilities to accomodate integrating Steam more fully into Fedora, so that things like Gaming Mode/Desktop Mode basically work as they do in SteamOS.

Doing it the way they do it, this makes it so you can use the various u-just terminal commands and pre-packaged flatpak apps to tweak things that basically affect or touch or may touch Steam.

So uh, right now, on my Bazzite Steam Deck, if I do:

rpm -qa | grep “steam”

(which is basically Fedora-speak for 'show me all installed libraries that have “steam” in them)

I get:

steam-1.0.0.85-3.fc43.i686

So that would be the current, Fedora 43 version of Steam, from the Terra repo, I think… its not the 44/Rawhide version.

Where the Terra repo is the community repo, sort of roughly analagous to the AUR, compared to mainline Arch libraries.

…pkgs.org/…/steam-0:1.0.0.85-3.fc43.i686.rpm.html

That command also lists out a number of steam-related utility libraries, which comprise parts of the core, ‘no touchy’, atomic part of Bazzite.