If one successfully defends an attack on a Phoenix Point Base, the attacking Pandoran Base should show on the map as it does when one successfully defends a haven. Mid to late in the game there a few havens to defend so the PP Bases are the main target of attacks. However, one must then scan and re-scan the area in hopes of finding the attacking base. Even with the tech to show Pandoran bases on scan they technically are not revealed. They show up as a "?" and must be explored to reveal the base. That's if one is lucky and scans the correct area.