Just like the Nexus S, the Galaxy Nexus features a Contour Display. The curved glass conforms to the side of your face and makes talking on the phone more comfortable.
The glass is fused to both the display and the display frame. So don’t crack the glass unless you’re good with a heat gun, or you’re fond of replacing the glass, display, and frame together ($$$).
Although fused parts make for difficult and expensive repair the result is tighter integration and in this case better front screen performance. Optically laminating the front cover to the display is important as it eliminates the air gap (where dust can settle), light refraction, and reduces thickness.