Valve has officially open-sourced Lepton, the compatibility layer designed for Steam Frame. The project, which enables the execution of Android games on the platform, is now available through the company's GitLab repository.
The initiative was first announced in March 2026, alongside the introduction of the Steam Frame Verified program requirements. Valve developed Lepton primarily to assist game developers in porting VR Android titles to Steam Frame, though other use cases remain possible.
The architecture of Lepton integrates components from Waydroid, Anbox, Halium, and Hybris. It combines proprietary Valve code with parts of the Android Open Source Project while mounting host system libraries, including graphics drivers, Steam libraries, and Vulkan layers.
By removing redundant Android elements, the tool aims to improve overall efficiency. The open-source release allows developers to study the implementation, modify the code for different applications, or create forks to add features and optimizations, similar to the ecosystem surrounding Proton-GE.
