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: Steering angle sensor inspection
With DSC
1. Remove the column cover. (See COLUMN COVER REMOVAL/INSTALLATION)
2. Disconnect the steering angle sensor connector.
3. Connect battery positive voltage to terminal A and ground to terminal F of
the steering angle sensor.
4. Turn the steering wheel to the right and left, and verify ...
Mazda 6 Owners Manual: Rocking the Vehicle
WARNING
Do not spin the wheels at more than 56 km/h (35 mph), and do not allow
anyone to stand behind a wheel when pushing the vehicle: When the vehicle
is stuck, spinning the wheels at high speed is dangerous. The spinning tire could
overheat and explode. This could cause serious injuries.
...