There are situations where one might want to track their hands, waist, feet, etc. but not have an HMD connected. This is especially true when trying to debug OSC trackers. Currently, all settings related to body tracking and FBT calibration are hidden when running VRC without an HMD connected. IK solver may not work correctly without a headset input, but that input can be provided or spoofed via OSC based on the documentation here: https://docs.vrchat.com/edit/osc-trackers