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: General procedures
Wheels and Tires Removal/Installation
The removal and installation procedures for the wheels and tires are not
mentioned in this section. When a wheel is removed, tighten it to 88-118 N·m
{9.0-12.0 kgf·m, 65.0-87.0 ft·lbf}.
Power Steering Components Removal/Installation
If any power steeri ...
Mazda 6 Owners Manual: Installation of radio system
If a radio system is installed improperly or if a high-powered type is used,
the CIS and other systems may be affected. When the vehicle is to be equipped
with a radio, observe the following precautions:
Install the antenna at the farthest point from control modules.
Install the antenna fe ...