G'MIC is a framework for image processing, providing
several different user interfaces to convert/manipulate/filter/visualize
generic image datasets, from 1d scalar signals to 3d+t sequences of
multi-spectral volumetric images.

The krita plugin requires the exact krita version it was built against, so the package shipped in Leap is "incompatible" with a different krita version.

Also, krita installed to /opt/kf5/ won't find the plugin in /usr/...