From raspberrypi.org's GPIO page:
A powerful feature of the Raspberry Pi is the row of GPIO (general-purpose input/output) pins along the top edge of the board. A 40-pin GPIO header is found on all current Raspberry Pi boards (unpopulated on Pi Zero and Pi Zero W).
Still very much a To Do page...
You can type:
% pinoutin the Raspbian OS and it will display information about your GPIO usage.
Links#
- Interactive GPIO Pinout
- GPIO page on raspberrypi.org