Valve seem to be pushing Linux support even harder now, with the announcement of the open source xrdesktop project from Collabora.
This new project, funded thanks to Valve, enables interactions with traditional desktop environments, such as GNOME and KDE in Virtual Reality. With xrdesktop, Linux window managers will be aware of VR and be able to use VR runtimes to render your desktop windows in a 3D space. It also gives you the ability to manipulate them with VR controllers, which sounds pretty fun.
Unlike other similar projects, xrdesktop is not limited to a VR only compositor, with an aim to integrate into existing Linux desktop environments. Collabora say this removes the need of running a dedicated compositor just for VR and makes it usable for existing setups, with the initial focus on GNOME and KDE but it's designed to work with any desktop.
They have a good roadmap of work up like support for OpenXR, support for Wayland and plenty more. You can see the full announcement and some instructions on the Collabora blog.