David - thank you so much for your correspondence and work to make those features possible!There's a manually edited JSON file for Byret on page 6 of this thread: Imaah Chehesti link
There are some new features like borders, which could be used on balkanized worlds or, in Byret's case, for a Larianz Autonomous Region on the planet.
In addition, you can place features where you want them, such as towns, cities, noble estates, etc. It doesn't take much JSON knowledge to understand how to just add an existing terrain feature type.