Power source for cables that connect into two white connectors on Dell 730xd server riser cards

Where do the other end of the cables that connect into these two white connectors (on the riser cards within a Dell Power Edge 730xd server) plug into to get its power (especially since I don't see anywhere that such a cable can be plugged into on the power supplies in a Dell PowerEdge R730xd server)? This URL has a picture of what I am talking about: https://imgur.com/gallery/jdemm4A