Just a collection of KSP items and scripts.
Everything in this KSP repo is released under the Apache License, Version 2.0. The Apache License is a very permissive OSS license -- you can release a modified version of anything in this repo under any license of your choice.
You can freely use, modify, distribute, and sell all included files/code without working about use -- personal or commercial.
I do ask, but not require, that any derivities and modifications also be made publically available to the KSP community.