KSSL v1.0
Initial release.
To install, simply extract a release zip into your [KSP Install Folder]/PDLauncher directory, replacing all. Steam should then launch KSP as it used to. Supports command line arguments like the good ol' days. You will probably have to reinstall this every update to KSP1.
This is a .net core 3.1 app and will prompt you to install that if not present. May work crossplatform if you can install it too, no idea, I only tested on windows.
License: MIT