Hardware What does the gamepad bottom slot use for?

[TonyGgse]

From manual it says that's a Accessory Connector, which for connecting external accessories to the Wii U GamePad, so what's the external accessories for GamePad? say, like what?

 

[Lotoonlink]

I think you're on the wrong section here but one accessory that used the bottom port was a charging stand where you placed the gamepad on it and it would charge; there were no cables running into the gamepad.

 

[Nollog]

None were released.
The E3 gamepads were just bolted on from what I saw.
They were just thinking like the Wii with all the nunchuck and classic controllers.

Also the copper pads are what the cradle charges it with not the adaptor hole.