`rusefi.bin` file is compiled rusEfi firmware. Sometimes you would have `rusefi_no_asserts.bin` variation of this file with fewer safety checks. `rusefi.dfu` is also compiled rusEfi firmware, that file is used for DFU mode of flashing. `rusefi.ini` is TunerStudio project template file, you would use it if you use TunerStudio software to tune your rusEfi unit. See http://www.tunerstudio.com/index.php/downloads for TunerStudio download See http://rusefi.com and https://github.com/rusefi/rusefi_documentation for more information about rusEfi