ref: 7e4104cabe8d995e40e552da2078fea87ff4ada6
dir: /LICENSE/
http://www.otakunozoku.com/1999/08/01/rednex-gameboy-development-system/ "The executables are free to use, either for personal hobby use, or full blown commercial productions--I know of at least a dozen commercial games you can purchase that are written with RGBDS--and the source code is free to modify. "The only thing I ask is that you do not charge for either distributing the executables or source code, and any derivative works you give credit to the original authors of the tools. That means you have to say 'Thanks' to the original authors SurfSmurf and Otaku."