This was discovered after Valve employee austinp_valve responded to a question in the Steam Big Picture forum about the future of the interface.
A console-like interface for users who connect their PCs to large monitors and television sets and use a controller rather than a keyboard and mouse was introduced in 2012 as part of the Windows 8 update. It served as the foundation for SteamOS, which was used to power the infamous Steam Machines.
Since then, it has received only a few minor updates, and users have expressed concern that it appears to be very out of date. The announcement of the Steam Deck coincided with the development of a new version of SteamOS, which will provide a much-needed UI refresh to many of Steam’s ageing components, including the Steam Deck.