Beta support for third-party PC VR headsets has been added to the Vive Ultimate Tracker. - Road to VR
Vive Ultimate Tracker Gets Beta Support for Third-Party PC VR Headsets
HTC has released a beta version of its Vive Ultimate Tracker that allows third-party PC VR headsets to support body tracking in certain apps. Previously, the device was only compatible with HTC standalone headsets, but now it supports OpenXR/SteamVR based PC VR headsets. Users can connect up to five trackers per headset for multi-point full-body tracking in supported apps. To access the beta, users can join the Viverse Discord and opt-in to the Ultimate Tracker PC Beta channel. For more information and to purchase the device, visit Vive.com. Full story available at Road to VR.
Source: https://www.roadtovr.com/vive-ultimate-tracker-quest-index-pico/