D3D9on12: Please background on ID3D12CommandQueue and last three ReturnUnderlyingResource parameters? (It's not obvious why they exist from a D3D9 perspective)

[m-7761]

There seems to be a lot of extraneous parameters on https://github.com/microsoft/D3D12TranslationLayer that maybe make natural sense to readers familiar with D3D12, but those are not the people who would need a "D3D9on12" translation layer after all. I want to use this to interface with OpenXR. It just needs to tap into the swap-chain. I'm not sure what on earth this other stuff is for or if there are dummy values that can be fed in their places, and I think it's a disservice to not have this explained in the documentation.