Ubuntu MATE 20.10 groovy
This "Pluma" code editor comes with Ubuntu mate
(screenshot from https://mate-desktop.org/)
In pluma > preferences > fonts & colors > Color scheme it states:
You can add a new color scheme by clicking on Add..., and selecting a color scheme file
You can remove the selected color scheme by clicking on Remove
Where are these files placed? and are they CSS files? I would like to create some additional themes for everyone to use.