It's probably just a more modern aircraft than you are used to. I haven't flown the 88 in many years and I'm not sure what you were looking at, or where it was connected, but consider that the 88 can use three sources of air for on ground air conditioning.
Ground Sources for Air Conditioning
There are three methods used to cool the aircraft on the ground:
• using a conditioned air source connected at either the left side of the fuselage at the mid cabin area or at the right rear of the aircraft.
• using the APU pneumatics to operate the packs or,
• using an external pneumatic source connected at the aft left side of the fuselage to run the packs.