These locks are intended to help prevent children from accidentally opening the rear doors. Use them on both rear doors whenever a child rides in the rear seat of the vehicle.
If you slide the child safety lock to the lock position before closing that door, the door cannot be opened from the inside. The door can only be opened by pulling the outside handle.

Locking, Unlocking with Door- Lock Knob
Trunk LidMazda 6 Owners Manual: Indication on Display
The Distance Recognition Support System (DRSS) operation status is indicated
in the active driving display or multi-information display. Regarding malfunctions,
check the vehicle conditions or have it inspected by an Authorized Mazda Dealer
according to the content of the displayed message.
R ...
Mazda 6 Owners Manual: Operating the Power Windows
NOTE
Each passenger window can be operated with each door switch when the
power window lock switch on the driver's door is in the unlocked position.
Each passenger window can also be operated using the master control switches
on the driver's door.
Normal opening/closing
To open the ...