CameraCalibration matrices origin in dng files

Hello,

I'm having trouble understanding how CameraCalibration matrices are calculated when converting CR2 to DNG. My understanding was that these matrices were dedicated to adjusting the color matrices of a given DSLR model to a specific camera of that model. But when I convert a CR2 file captured with my own DSLR to DNG, I can see in the DNG's metadata that these matrices are not set as identities. When I look in the dcp file corresponding to my DSLR, it does not contain any CameraCalibration matrix. I therefore deduce that the DNG converter calculates these matrices and adds them in the metadata. However, I can't find a clear explanation anywhere on how and from what parameters they are calculated.
In the DNG's metadata's both ProfileCalibrationSignature and CameraCalibrationSignature are set to "com.adobe" what indicates that the CameraCalibration matrices should be used. The tag ProfileCalibrationSignature is in the dcp file but the tag CameraCalibrationSignature is added by dngConverter.
I think I misunderstand the true role of the calibration matrices and any clarifications on all of that would be very helpful for me.

Thanks a lot