Presumably code that attempted to toggle a led, but it wasn't setup, and it's not in any other examples. Kill it for now. Reported-by: stefanct on irc.
------------------------------------------------------------------------------ README ------------------------------------------------------------------------------ This example implements a USB CDC-ACM device (aka Virtual Serial Port) to demonstrate the use of the USB device stack. Board connections: ------------------ CN5 (USB_OTG_FS) USB acting as device, connect to computer