The concept
The parking brake is primarily intended to prevent the vehicle from rolling while parked; it brakes the rear wheels.

See also:
Remove attached partsfollowing use
Remove auxiliary mirrors, roof or rear luggage
racks which are no longer required following
use.
Attached parts on the vehicle impair the aerodynamics
and increase the fuel consumption. ...
Vehicle equipment
All standard, country-specific and optional
equipment that is offered in the model series is
described in this chapter. Therefore, equipment
is also described that is not available in a vehicle, ...
Comfort position
In the comfort position, the roof is not fully open.
This reduces wind noise in the passenger compartment.
Every time the glass sunroof is opened or closed
completely, it stops in the comfort p ...
