20mm cannon. Centerline pod would also take a fuel tank, or probably a chaff and flare dispenser or anything else mission-necessary. Outboard pylons appear to be fuel. Can also carry luggage compartments for getting pilot's golf clubs to Homestead, or other Florida base with nice weather and golf courses.
F-4E incorporated the cannon in the nose. Made it harder to shoot the nose-gear off.
The outboard pylons would also hold the 20mm gun pod. I saw that configuration many times at the Kunsan Resort & Spa.
Very cool actually, three 20mm pods hanging off the beast - whatever the target is, death will be very quick!