I've the information that it's like GitHub or Codeberg, but its looks are different. I've created an account anyways.
As mentioned, I am sorry, but I am not the author. Raju Gandhi is.
It should be possible to contact him if required:
Raju has been writing software for over two decades. He's a software developer, architect, consultant, author of multiple books, teacher, and a regularly invited speaker at conferences around the world.
Related: https://rajugandhi.com/