Pontiac 2008 Grand Prix Owner's Manual page 60

Driver Side shown, Passenger Side similar
If your vehicle has roof-rail airbags for the driver, right
front passenger, and second row outboard passengers,
they are in the ceiling above the side windows.
1-56
CAUTION:
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If something is between an occupant and an
airbag, the airbag might not inflate properly or
it might force the object into that person
causing severe injury or even death. The path
of an inflating airbag must be kept clear.
Do not put anything between an occupant and
an airbag, and do not attach or put anything
on the steering wheel hub or on or near any
other airbag covering.
If your vehicle has roof-rail airbags, never
secure anything to the roof of your vehicle by
routing the rope or tie down through any door
or window opening. If you do, the path of an
inflating roof-rail airbag will be blocked.