This is their license
Copyright (c) 2021, Secret Weapons. All rights reserved.
This code is for non-commercial use only. It is provided for research and evaluation purposes.
If you wish to obtain commercial license, please contact: mixbox@scrtwpns.com
So useless to Krita as is. I don’t even know if writing an original code, but using their approach or ‘formulas’ would be legal.
Not forgetting we would need a enthusiast coder to do this, as the main team don’t consider Real Pigments an urgent need.