From Halopedia, the Halo wiki
Ap'ot is an orbital port city in the Y'Deio system. The port consisted of a collection of long jetties and booms arranged along a central spine, with each spine connected to a central hub.
After the collapse of the Covenant, many Kig-Yar stole Covenant frigates and Covenant corvettes and brought them to Ap'ot. By 2553, Ap'ot, like many ports in the Y'Deio system, was becoming crowded. This caused prices for docking a ship to rise, even smaller ships like Phantoms cost 100 credits for a day. The Skirmisher, Chol Von, stored her ship Paragon in the port and decided to gather a crew to steal Pious Inquisitor here.