Porsche Boxster Owner's Manual page 44

Seat backrest
Folding forward
Pull up lever H in the side part of the backrest
and fold the backrest forward.
Folding back
Tilt back and engage the backrest so that it cannot
tip forward when the car is braked.
Sports seat only
The seat belt can be fixed to the seat backrest with
the retaining strap, so that it can be reached more
easily for buckling up.
42
Controls, Instruments
Release button J at the top of the retaining
strap, insert the seat belt and fasten the strap
once more.