Displays in the following cases:

Stop Vehicle in Safe Place Immediately
Message Indicated in Multi-information DisplayMazda 6 Owners Manual: Removal/Installation
To remove the head restraint, pull it up while pressing the stop-catch.
To install the head restraint, insert the legs into the holes while pressing
the stop-catch.
WARNING
Always drive with the head restraints installed when seats are being used
and make sure they are properly installed: Dri ...
Mazda 6 Owners Manual: Front buckle removal/installation
1. Perform the following procedure for vehicles with seat belt warning.
(1) Disconnect the negative battery cable.
(2) Remove the front seat.
(3) Disconnect the buckle switch connector.
2. Perform the following procedure for vehicles without seat belt warning.
(1) Remove the console.
...