IFixit replacement screen has a film on the back of it.
There is a shiny film on the back of my new IFixit replacement screen for my iPhone 11 Pro. I looked at the old screen and there was no film on it. I can't tell if it's a protective film or part of the screen. There are two orange things connected to the film on the new screen and they could be tabs for pulling the film off but I'm not sure.
I don't see anything in the picture of the screen that iFixit sells; can you add a picture of your new screen to your question?
iFixitでの質問に画像を追加する方法
Jerry Wheeler さんによる