It's an incredibly promising project and work on it has continued recently, They even had people getting involved through the Google Summer of Code (GSoC) which produced some fun results.
The major one is a new Virtual Reality Keyboard. Since the OpenXR doesn't expose an API for text input, they had to roll their own system. Student developer Remco implemented this with support for emojis and 56 languages, which required work to add Unicode support to LibInputSynth too. With the way it was implemented it's possible to change the entire keyboard layout too.
Other work included adding loading and rendering of GLTF models which they say "enables xrdesktop to use assets like VR controller models and 3D environments.".
All sounds good and a new tagged release of xrdesktop is due soon.