Front Sensor Assembly Screws on the iPhone 11 replacement screen

One of the screws is tiny and located in the top left (facing the back of the panel In the sensor aray.

It holds the right angled cover for the chip behind the proximity mic grill thingy. Sandwiched between the screen chip and this bracket is a slide on auxiliary plate to retain the long square chip.

The screw in question is a y000 and is about 1.2 mm long.

Either the screw or auxiliary plate can be lost and not effect the functions of the phone if one or the other is lost during repair. Even though it's unprofessional and improper to leave out plates fasteners etc. It will get the job done.

Some aftermarket parts don't bother with some dedunant screws sometimes but those are typically parts you'd want to avoid as they obviously cut corners in manufacturing and could have faults down the line post repair.