Fan pins. All these extras on the 3b+ and now the 4 and all I really wanted was an extra pair of pins (5v/gnd) to plug a doggone fan into without losing the ability to plug a standard 40 pin cable into my GPIO header.
My Autonomous Robot Project and a few of my other projects below.
I am pretty sure they would not add an extra power pair of pin even for RPi3.. Mainly because it is quite pointless, you could connect the fan to the existing gpio by other methods like hacking the cable a little
My website is at https://pratt.ml
Hope it runs (which it wont)