Go to the link below and look at about the 10:40 mark. It explains what is going on.
Looking through the parts list I can't find that part individually, so your suspicion is correct that a new roof might be the reply from Porsche.
It's there to pull that part of the liner nice and tight along the side of the roof frame. To be frank it didn't seem to do a whole lot when I was playing with the roof while installing the liner. You could probably remove the cord completely with little effect. It won't hang loose as there is another cord running along the side that still holds things tight.
Looking through the parts list I can't find that part individually, so your suspicion is correct that a new roof might be the reply from Porsche.
It's there to pull that part of the liner nice and tight along the side of the roof frame. To be frank it didn't seem to do a whole lot when I was playing with the roof while installing the liner. You could probably remove the cord completely with little effect. It won't hang loose as there is another cord running along the side that still holds things tight.