I think maybe the authors are using a strange definition of "fork": if you fork a project and then take it to a different direction, making incompatible changes

I think maybe the authors are using a strange definition of "fork": if you fork a project and then take it to a different direction, making incompatible changes from upstream then it's somehow not a fork anymore. I'm not too sure though if that's the thinking. (reading from https://gren-lang.org/book/faq.html https://gren-lang.org/book/faq.html) Seems like a fork to me. Or maybe the thinking is that they'll rewrite it from scratch at some point which would make it not a fork from code perspective.