Stardust XR is a display server for VR and AR headsets on Linux-based systems. Stardust provides a 3D environment, where anything from 2D windows (including your existing apps!), to 3D apps built from objects, can exist together in physical space.
An install guide for a full working Stardust setup can found here: https://stardustxr.org/docs/telescope/install
Development build instructions can be found here: https://stardustxr.org/docs/dev-setup/dev