The rear armrest in the center of the rear seatback can be used (no occupant in the center seat) or placed upright.

WARNING
Never put your hands and fingers around the moving parts of the seat and armrest:
Putting your hands and fingers around the moving parts of the seat and armrest is dangerous as they could get injured.
Split Folding
Head RestraintsMazda 6 Owners Manual: Transaxle range (tr) switch inspection
Operating Inspection
1. Verify that the starter operates only when the ignition switch is at the
START position with the selector lever in P or N position.
If not as specified, adjust the TR switch.
2. Verify that the back-up lights illuminate when shifted to R position with
the ignition ...
Mazda 6 Owners Manual: Scheduled Maintenance (Mexico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
Driving on rough or muddy ...