...that you will have to remove and scrape off before installing the new liner and backing.
The PO “hot glued” a piece of fabric on to the sunroof thing for a headliner. 99% of the time I don’t notice how bad it looks, however it made it to the list of things to fix.
Is the original headliner for the sunroof just fabric? Perhaps there is cardboard of something as a backer?
...that you will have to remove and scrape off before installing the new liner and backing.
The backing consists of a stretched piece of cloth to which the foam-backed material is glued.