SteamOS is the Linux-based operating system that Valve developed for its Steam Deck handheld, and it can also be installed on personal computers without official support from Valve. Since version 3.0 it has been based on Arch Linux and is built to run the Steam client and games. The core operating system is free and open-source software, while the Steam client remains proprietary. Users install it on their own device, and games are delivered through Valve's Steam platform.
Valve Corporation is headquartered in Bellevue, Washington, so it is subject to US law, including the CLOUD Act for data it controls. Valve's privacy policy states that personal data may be transferred outside the EEA, the UK and Switzerland. It cites the EU-U.S. Data Privacy Framework and Standard Contractual Clauses as transfer safeguards and names an EU representative in Hamburg, Germany. The policy does not state where user data is stored. For a European organisation, the Steam account and the Steam client remain under the vendor's control; the open components of SteamOS can be studied, but they do not remove that dependency.