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: If You Must Use the Front Seat for Children
If you cannot put all children in the rear seat, at least put the smallest children
in the rear and be sure the largest child up front uses the shoulder belt over the
shoulder.
NEVER put a rear-facing child-restraint system on the front passenger seat whether
your vehicle is equipped with a o ...
Mazda 6 Owners Manual: Clock spring inspection
1. Remove the clock spring.
2. Inspect for continuity between the clock spring terminals using an
ohmmeter.
If not as specified, replace the clock spring.
Note
When the vehicle-side connector of clock spring is disconnected,
the terminals 1A,1B, 1C and 1D are shorted to prevent ...