what is the opening in the middle of the back seat for that opens into the trunk ?
openng in the back seat on 1998 Pontiac Bonneville
The door in the back seat into trunk is to allow you the flexibility to load long objects into the passenger area instead of having them stick out the back of the trunk. This may allow the trunk lid can close completely in some cases where it may not have.
it's for putting long items like skis or wood in the trunk. i have a 97 & the sales brochure shows skis & poles going through the hole to make them fit