Ok since this is not really answered... Hypothetically, If I'm a maintainer of this project. I decided I hate the implementation, it's naive, horrible performance, weird edge cases. I'm wiser today than 3 years ago.

I rewrite it, my head full of my own, original, new ideas. The results turn out great. There's a few if and while loops that look the same, and some public interfaces stayed the same. But all the guts are brand new, shiny, my own.

Do I have no rights to this code?