If it's the film on the outside of the large windows in the heads, it's not a film. I removed mine quite easily with acetone.
Lagoon says "solvent".
I replaced ours with laser cut film supplied by a sign writer. Ours is now horizontal stripes, rather than the dots on the original. Looks good, and does the job. Easily replaced if subject to further wear and tear.
Bob
Casablanca
Lagoon 420 # 86
PS Just realized the topic is
cabin windows. Tried to delete my post but it doesn't seem possible?