Is the marker reference for Customed Landmarker only used for QA purpose or is it also used for tracking as well like the usual marker tracking?
The marker reference for Custom Landmarker is only used for QA purposes. It is not used for tracking. The Custom Landmarker feature allows you to create your own set of markers for use in the Face Tracking component, but these markers are not used for tracking. Instead, the Face Tracking component uses its own internal tracking algorithms to detect and track the face in the camera feed.