Implementation of the autograd graph

Things have changed (recently?) with .creator becoming .grad_fn and other stuff disappearing.

Is there a documentation somewhere about the precise implementation of the autograd graph? This should probably be the right place, but the current content is quite succint:

How autograd encodes the history

Ideally, a function in the documentation to visit all the nodes of the said graph would be helpful. That would cover well how all this is done.