And the A-1 Skyraider. And the A-26 Invader. And the A-20 Havoc. And the SBD Dauntless. And … 
Edit:
Page 12 of the manual, §1-59:
In other words, these are stowage bins for some of that kit, allowing it to be plugged in yet stored out of the way when not needed — or so I assume.

Edit:
Page 12 of the manual, §1-59:
PERSONNEL GEAR RECEPTACLES. Receptacles for plugging in personnel gear adapters (…) The receptacles have provisions for connecting simultaneously, the oxygen mask, anti-g suit, headphones, and microphone cord.
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