So really, all modern browsers are either forks of KHTML / KJS or are based on the Mozilla codebase. But, at least right now, there are 3 separate engineering teams working on 3 independent codebases. Which hopefully will mitigate some of the issues you get when one company completely controls a software “ecosystem”.
Chrome is definitely a fork of Safari in a way. Or more accurately, Blink is a fork of Webkit.
So really, all modern browsers are either forks of KHTML / KJS or are based on the Mozilla codebase. But, at least right now, there are 3 separate engineering teams working on 3 independent codebases. Which hopefully will mitigate some of the issues you get when one company completely controls a software “ecosystem”.