File: Makefile (Probably text)
File: Radio.pde (Processing (programming language) script)
File: blink.c (C source)
File: radio.asm (Assembly language source)
File: radio.bas (BASIC and variants)
File: radio.c (C source)
File: radio.hex (hexadecimal ASCII encoded binary)
File: radio.mac (Probably text)
File: radio.map (Probably text)
File: radio.o (object files directly from the compiler)
File: radio.out (Output of some program; probably text)
Image: arduino_usb.jpg