2x2 unpopulated pins on ATMEGA16U2

Other Hardware 3rd Party Boards
1

Hi,

What are those 2x2 header pins that are unpopulated?
It's connected to PB4 to PB7 on the ATMEGA16U2.

Thanks,
RI

2

The ATMEGA16U2 is an IC. It doesn't come with any headers.

3

I know that, but PB4-PB7 is connected to a unpopulated header on uno, mega and even due.
What is it meant for?

header.png

4

Some more information in this post:

http://forum.arduino.cc/index.php/topic,130986.0.html

They say maybe an unimplemented feature. In any case, it's just a breakout for those four pins. Feel free to mount pins in it if you want.