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: Transmitter
NOTE
(With theft-deterrent system) The hazard warning lights flash
when the theft-deterrent system is armed or turned off. Refer to Theft-Deterrent
System.
(With the advanced keyless function) A beep sound can be heard
for confirmation when the doors are locked/ unlocked using the k ...
Mazda 6 Owners Manual: Supplemental Restraint System Components
(With Front Passenger Occupant Classification System)
(Without Front Passenger Occupant Classification System)
Driver/Front passenger inflators and air bags
Roll-over sensor (some models), crash sensors, and diagnostic module (SAS
unit).
Seat belt pretensioners
Front air bag sensor ...