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: Lane Departure Warning
If the system determines that the vehicle may deviate from its lane, the lane
departure warning (beep sound, rumble sound*1, or steering wheel vibration) is activated
and the direction in which the system determines that the vehicle may deviate is
indicated in the multi-information display and ...
Mazda 6 Owners Manual: Neutral switch inspection
Note
Perform the following inspection only when directed.
Continuity Inspection
1. Disconnect the negative battery cable.
2. Remove the neutral switch.J5 MANUAL TRANSAXLE REMOVAL/INSTALLATION.)
3. Inspect for continuity between the neutral switch terminals using an
ohmmeter.
If the n ...