I had posted this as a reply to another post, but I think it is important enough to have its own dedicated discussion, that is why I am re-posting it here.
You had mentioned that you will add marker size estimation in this release. I found out that you have added a header file and a .h/.cpp containing the logic for querying markers based on openxr calls. Namely: XR_ML_marker_understanding.h and MarkerTracking.h/.cpp files.
I want to implement the marker tracking using these calls. However, I have been unable to find any documentation regarding these calls and their arguments. As you may know, in OXR usually we need to supply a chained data structure for the functions. In some occasions, one needs to call a method multiple times to get the correct result. These characteristics makes working with OXR to require the access to the respective docs. Hence, it would be really helpful if you could provide the docs regarding these calls. I am writing this post since I have been unable to find any information on OpenXR Specs page nor in the aforementioned files.
Moreover, trying to initialise function pointers such as xrCreateMarkerDetectorML, xrDestroyMarkerDetectorML, etc. using the latest standard OpenXR Loader SDK (version 1.0.31), fails. Your documenation regarding OpenXR Runtime Setup, also, does not list the extension XR_ML_MARKER_UNDERSTANDING_EXTENSION as a supported extension. Hence, the question: How can I build openxr-loader with this extension enabled? Or, can you give us access to the openxr-loader library that you use for this extension?
tl;dr: The openxr methods are there, where are the docs? And how to get the extension in openxr-loader library?