Why does chime sound when door is open and key removed on 97 t- bird?

The chime in a 1997 Thunderbird sounds when the door is open and the key is removed to alert the driver that the keys are not in the ignition while the door is ajar. This serves as a reminder to prevent locking the keys inside the vehicle and to ensure the driver is aware of the door being open. It's part of the vehicle's warning system designed to enhance safety and convenience.