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: Front door speaker removal/installation
1. Disconnect the negative battery cable.
2. Remove the front door trim.
3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Front Door Speaker Installation Note
Attach the speaker with the wiring harness placed in the groove of the door
unit panel.
...
Mazda 6 Owners Manual: Operating the Satellite Radio (Some models)
What is satellite radio?
With over 130 channels, SiriusXM Satellite Radio brings you more of what you
love. Get channels and channels of commercial-free music, plus sports, news, talk,
entertainment and more.
Commercial-free music from nearly every genre
—rock to pop, hip-hop to country, ja ...