In retrospect it may have been a better choice to use a 2×3 IDC connector and route the signals using the AVR ISP standard ... The USBtinyISP is an In-System-Programmer based around an ATtiny2313 ...

Instead of following in the footsteps of the USBtinyISP, [Dilshan] is using a PIC18F as the main microcontroller in the programmer. This chip was chosen because of its built-in USB functionality.