No, it doesn’t make sense, but that’s just the way it is. For any other PCB design tool, creating a custom-shaped board is simply a matter of drawing a few lines. Fritzing is different, though.

In Sept. 2013, [Squonk42] posted up on the Arduino forums requesting the schematics and editable design files for the Arduino Yun, and he still hasn’t received them or even a response.