To contribue, simply fork the repository, make your changes, and then create a pull request. Your changes will be validated, and if successful they will be added to the primary code base. Any changes made to this repository that are proven to be counter-active, mischievous, or otherwise unneeded will be removed and the contributing user will be unable to make changes to this repository.
This project requires GameMaker Studio 2 in order to open and make changes to it. No liscense should be required, however that is untested.
Create issues to your heart's content. They let me know what needs to be fixed and what should be tweaked or added. If enough of a community grows around this project, I will try and interact with it as best as I can.