Hello Whemoon !
Sorry for the late response, I hadn't visited this forum for some time.
You can find the new versions on the site dedicated to Rhino/grasshopper plugins: https://www.food4rhino.com/app/esquissons.
About the source code, you can find it on GitHub: https://github.com/TheoArchi/EsquisSons ; But this is only the source code of the latest version, the older versions were not compiled. So the code could be directly explored during use.
Enjoy the sketch !