This feature prevents all power windows from operating, except the driver's power window. Keep this switch in the locked position while children are in the vehicle.
Locked position (button depressed):
Only the driver's power window can be operated.
Unlocked position (button not depressed):
All power windows on each door can be operated.

NOTE
When the power window lock switch is in the locked position, the light on each power window switch, except for the driver's power window switch, turns off. The light may be difficult to see depending on the surrounding brightness.
Operating the Power Windows
Moonroof (Some models)Mazda 6 Owners Manual: Air intake actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air intake actuator.
2. Verify that the air intake actuator operates as shown below.
If not as specified, replace the air intake actuator.
...
Mazda 6 Owners Manual: Seat Belt Extender
If your seat belt is not long enough, even when fully extended, a seat belt extender
may be available to you at no charge from your Authorized Mazda Dealer.
This extender will be only for you and for the particular vehicle and seat. Even
if it plugs into other seat belts, it may not hold in the ...