I was looking for a library implementing a specific protocol for my favorite programming language.
I found one, but noticed that it started out as a straight port of another project. However, in each code file the author have replaced the original copyright with his own.
I opened an issue and pointed out that the copyright can't just be replaced. He asked me what he should have done. And that's why I'm here.
When you start a port it is quite similar. But then the projects probably will diverge depending on the direction they take.
So how should the copyright be handled in these cases?