segatools.ini tells the emulation layer how to fake those hardware responses. It is the "lie" that convinces a game (e.g., Initial D The Arcade , Border Break , or Chunithm ) that it is running on genuine arcade hardware.
For power users, segatools.ini supports direct memory patches. This allows you to bypass region locks, remove resolution caps, or unlock hidden test menus. segatools.ini
Even on modern archiving projects (like the for Dragon's Dogma Online arcade), the devs have kept the .ini format because it is: segatools
[vJoy] ; Map left stick to steering wheel steering=0x01 throttle=0x02 brake=0x03 ; Invert axis if the car turns the wrong way invertSteering=0 invertThrottle=0 Initial D The Arcade