Possibly a seatbelt warning module connector.
No power windows, or locks on the car.
On my 74 that is for the seat belt warning system. I took mine out it has a harness that runs under the carpet to the sensors under the seat. I have the harness if you want it and the sensors also I believe.
In a 74, that plug is for the seat belt warning system if it is on the passenger side. I just removed all that from the harness on my 74 Duster prior to reinstallation.
Cley
On my 74 that is for the seat belt warning system. I took mine out it has a harness that runs under the carpet to the sensors under the seat. I have the harness if you want it and the sensors also I believe.