I thought it held the brakes on by electrically activating the calipers ,via a small motor and a screw thread onto the pads.
I know there is no longer any type of mechanical 'hand brake ' on these cars - not of the style I and h5djr have been used to for many years .
What you describe is like the old Line Lock used in Drag Racing back in the 60s 70s etc ? Push the pedal, pull a switch and a valve shuts in the lines holding brake pressure in the lines, thereby continuing to activate the lights ?
You don't have to pull any switch - it happens automatically when you have stopped, and comes off automatically when you move away.