You can find the forks by looking in the "network" part of the UI.

I do agree that GitHub could do more to highlight forks and their relationship to one another. But I don't think the current way - having an open pull request - is the only way to do that.

As a former maintainer, I am very in favor of this move. After having spent 10 years or so being hounded with "Any update on this?" and "Can we get this merged?", I don't think I would ever do it again as long as there aren't controls in place to be able to set the expectation that the code is free to do with as you will, and please go ahead and fork if you want it to do something different.