Facebook and Oculus have announced OpenXR support in a prototype version available for developers in an upcoming update. The Oculus PC and Mobile SDKs will include the OpenXR API for native C/C++ development on Oculus Rift and Oculus Quest.
OpenXR is a royalty-free open standard from The Khronos® Group created for the development of high-performance VR applications that run on multiple platforms. OpenXR aims to simplify VR development by enabling developers to reach more platforms while reusing the same code. To learn more about using OpenXR to develop VR apps, visit the OpenXR 1.0 Specification page at the Khronos website. Khronos also provides API reference documentation and a PDF reference guide that provides an overview of the API.