Bottle holders are on the inside of the doors.

CAUTION
Do not use the bottle holders for containers without caps. The contents may spill when the door is opened or closed.
Cup Holder
Storage CompartmentsMazda 6 Owners Manual: Dsc on-board diagnosis
On-Board Diagnostic (OBD) Test Description
(See ABS (ABS/TCS) ON-BOARD DIAGNOSIS)
DTC Table
PID/DATA Monitor Table
Active Command Modes Table
...
Mazda 6 Owners Manual: Discharge headlight control unit removal/installation
Caution
Incorrect servicing of the discharge headlight control unit could
result in electrical shock. Before servicing the discharge headlight control
unit, always refer to the Discharge headlight service warnings. (See
DISCHARGE HEADLIGHT SERVICE WARNINGS)
When replacing the discharg ...