Download the repository as a zip, but don't unzip. In Blender, go to Edit > Preferences > Add-ons > Dropdown in the top right > Install from Disk and select the zip file. Edit a subset of color ...
Word on the street: Blender 5.0 may bring templated “presets” to Geometry Nodes and compositing. Andrew Price just teased it, and PR 145645 looks like the code behind it. Blender educator Andrew Price ...