Inside Unreal: Animating with the Control Rig Sample Project

At time code 53:34 in the livestream Jeremiah shows Additive Control Rig track.

Can the Additive Control Rig track affect CR Controls? or just Bones?

What would be a good way to bake motion capture to the Control rig so that we can then use the Additive Control Rig Track to adjust it with keyframing?