Hello to everyone!
I really don't know how I can name this part, so suggestions would be welcome!
But I can describe for what I used this part.

Some time ago I broke my tablet screen, and the replacement quality wasn't good.
Because of it, I decided to reglue the screen tablet frame.
To do it properly, I needed some kind of spacer to provide a uniform press.

So, long story short, if you disassemble your tablet, this frame can help you to assemble your tablet properly.