One of my cars had it. There are some decent YouTube videos of various techniques. I tried everything on mine. A plastic scraper with a heat gun or adhesive solvent made progress, but I didn't have the patience. Even sanding the bumper and repainting made a mess, because I didn't get it
all off. In the end, I got a new bumper (Black '99).
I think it's made by 3M. Contact customer service, maybe they can suggest something.