Steam OS

 I found a copy of the Steam Iso and want to see it boots. It has to be Installed and takes over the disk just like Endless OS. I would try it on Box Utility.

SteamOS

The last version | Released: 2.195 | July 17, 2019

SteamOS – a Linux distribution developed by the Valve Corporation, an American company, specializing in creating computer games.

The system is based on the Debian stable branch and provides two default profiles:
– GNOME desktop containing basic programs from this environment
– Big Picture – full screen mode

SteamOS additionally includes proprietary drivers and a newer LTS Extended Support Kernel.
The system is mainly designed to work with the Steam platform and run games available on Steam.
A desktop profile based on the GNOME desktop and Debian repositories allow the installation of additional programs and their operation on the system.

The underlying system is open source, but the Steam client is closed (proprietary) software.
SteamOS is available for 64-bit machines equipped with a motherboard with UEFI.

From January 21, 2014 the SteamOS has been released for older 64-bit machines running with BIOS.