A Swift program to convert GIMP Palette Files (gpl) to Apple Color Picker (clr) files that I whipped up one afternoon.
Basically I had a number of palette files for GIMP that I thought would be nice to have as color library in macOS. This program will process all the files in a particular directory (in the code, it's ~/Downloads/Embroidery Color Palettes) and write out a .clr file in the /Users/<user>/Library/Colors/<Palette Name>.clr directory.
Hope this helps someone!