The LUFA version is 100807, as in the hardware-pinoccio repository. This version is required for both DFU and USB serial firmware. The arduino-usbdfu directory contains the DFU bootloader on the 16U2 ...
[1] A. Sotiras, C. Davatzikos, and N. Paragios, “Deformable medical image registration: A survey,” IEEE Trans. Med. Imaging, vol. 32, no. 7, pp. 1153–1190, 2013 ...