1998 xlt 4.0 beeps

i gave my car in for brakes change and after i got it back i noticed that it does 1 long beep after you open the door if the car is on. i dont remember it doing it prior. can anyone tell me what this one long beep is and it only happens if the car is turned on and you open the door. dont confuse this with the repetitive beeps that the car does when door is open and you have the key in, this one is not repetitive.

i gave my car in for brakes change and after i got it back i noticed that it does 1 long beep after you open the door if the car is on. i dont remember it doing it prior. can anyone tell me what this one long beep is and it only happens if the car is turned on and you open the door. dont confuse this with the repetitive beeps that the car does when door is open and you have the key in, this one is not repetitive.
Yeah mine does it too it's a safety feature I believe