It's extremely high level and vague presumably by intention. If you don't have a grounding in networking, BGP, traffic engineering (MPLS, SR, related concepts), you won't be able to make out much about it. If you do, you'll just infer that they're doing a form of "egress peer engineering". On top of that it sounds like they're potentially using whitebox switches at the edge and terminating BGP peering sessions on servers which are programming the forwarding state on these white boxes.