Couldn't find that in my 21 manual, but just for kicks I tried it on a
slight incline in my driveway and find the integrated hydraulic brake master cylinder starts applying the actual brakes at about 1/2 to 3/4 inch pedal depression, fluid level in reservoir filled just below the bottom of the cap, hope that helps.
What surprised me while doing this test is the VESS actually is additionally motion activated. The car was silent until the very slow roll back in
neutral approached about one full wheel rotation, thought previous to this test it was strictly activated by gear (drive or reverse) application.

Keep in mind the manual referred to also requires the owner to check for loose wheel lug nuts monthly- don't even own a torque wrench to do that and don't remember seeing that specifically in the "accessories" available in their website.
Also mentioned as an owner requirement- yearly "Lubricate door checker" ... don't have a clue what that is either.