Oh gotcha, yup, I was talking about Auto Parking brake.
Here is the manual:
https://5thgenrams.com/wp-content/uploads/2018/07/2019-RAM-1500_All_New-OM-3rd_R2.pdf
On page 297 it talks about the Autopark system and how it can be operated and not operated.
If the vehicle is not in PARK and the driver exits the
vehicle with the engine running, the vehicle may AutoPark.
AutoPark will engage when all of these conditions are met:
• Vehicle is equipped with a rotary shifter and an 8-speed
transmission
• Vehicle is not in PARK
• Vehicle speed is 1.2 MPH (1.9 km/h) or less
• Driver’s seat belt is unbuckled
• Driver’s door is ajar
• Brake Pedal is not depressed
The MESSAGE “ AutoPark Engaged Shift to P then Shift
to Gear” will display in the instrument cluster.