WebXR Input Profiles Loader in Unity. Based on WebXR Input Profiles.
You can try the demo here.
The package is intended to be used with WebXR exporters in general, and not only with WebXR Export.
The package uses glTFast to load the models, and Unity's package of Newtonsoft Json.NET to parse the profiles.
You can get the package from 
You might need to add Shader Variants of the Input Profiles Models to the build for the shaders to work. More info about that can be found at the glTFast docs.