We just don't have the information available to know the full what and why.
Since the units are programmable, we can not assume that yours came with the same eeprom programming of someone else's.
Notice in the picture that it is sitting on a plastic bag with the word "AmazonKindle" on it. Which might imply that someone re-programmed it from the default 5v mode.
I can not tell from where I sit if yours has been re-programmed (or the one pictured has been).