These properties are set when you use save_for_backward() during the forward pass.
This should only be used for input/output Tensors. Other things should be saved in ctx.my_tensor=my_tensor.
SavedVariable is any Tensor that is somewhere in the graph.
But here, since every cpp implemented Function is different, there is no common API to expose what they saved. Such API would be tricky as Functions save very different things and you would have no guaranty when you have  a Function what you would find there. Also this would create even more headaches about cycle references of python objects