I barely understand this stuff. I know that everything is a file. In Inkscape, the files are very accessible directly to edit, unlike the proprietary programs that hide that stuff from you. What we are doing is simply making a numeric description of colors and putting it in the form of a file that Inkscape can read. The GFUI must have some part of its programming that reorders the different colored objects according to a certain scheme. That allows the catalog files to order their cuts automatically for best effect.
I did this on Windows 10. You might run into permission problems poking around in the install directory. You’ll have to allow it as administrator.
This is the simplest format to make. Use a Notepad to make the file and save as plain text with the extension .gpl.
I guess this would make a good video tutorial!