Forks diverge. Blink is a fork of Webkit, but Blink hardly resembles Webkit anymore. Blink doesn't pull any changes from Webkit

https://en.wikipedia.org/wiki/Fork_(software_development)

>Eric S. Raymond, in his essay Homesteading the Noosphere,[12] stated that "The most important characteristic of a fork is that it spawns competing projects that cannot later exchange code, splitting the potential developer community"

At this point I just want to add that I'm not a developer and I don't actually know much, I just read stuff online. But yeah, Edge isn't a fork