Chosen Solution

And what is it’s purpose? It is the piece that is glued to the inside of the front glass on the iPhone 4.

thats what gives the camera focus. if you dont have a piece of glass in front of ur camera your images would be blurry and not focused. also it helps with the zoom and magnification.

That is so wrong. It does neither of those things. It simply holds it into position. The camera is fixed focus to start with!