MechJebLib.dll has no references to MJ/Unity/KSP (pure C#) MechJebLibBindings.dll has references to Unity/KSP (conversion glue) alglib.dll is extracted so that MJLib+MJ can both reference it Jetbrains.Annotations is included so MJLib can use it without referencing Unity and MJ now uses the updated nuget package as well (Unity version is old and now will never get updated)