Valve released a new Steam client beta that brings the Linux version inside its own Steam Runtime container, the same containerization technology already used for Steam games. The experimental SteamRT3 build aims to deliver a more consistent experience across different Linux distributions by running the client in an isolated environment rather than directly on the host system.
The containerized client also marks Steam's transition to a 64-bit architecture on Linux, moving away from the 32-bit client that has been standard for years. Users can opt into the SteamRT3 beta through a dedicated setting in the Steam beta client labeled "Use experimental SteamRT3 Steam Client."
Valve is distributing the SteamRT3 beta alongside the regular Steam beta client, making the containerized version entirely opt-in for now. More details are available in the official announcement on Steam Community.