When you get a 7 segment display, there is a film over the front, is this supposed to be removed, left on, do not matter, protection for ultrasonic cleaners
Leave it on until you mount the display in an enclosure to protect against accidental scratches, etc - then rip it off. It's only there to make sure you get it from the manufacturer/distributor scratch-free.
Many Thanks
And so you don't have to clean it before you mount it on the real device and sell it. Someone else will worry about it then.