Useful option was implemented, it helps save engine in some cases, bad fuelpump(s), bad fuel, bad tuning, broken config, etc.
At one car it could be used for CheckEngine light, and another for sound beep (car alarm siren) inside car.
It could light at cranking to be sure that light still not broken, same as OEM CE light.
ADC channel useful for fuel or oil pressure or oil temperature sensor at spare channel.
Knock - warning when knock retard applied.
CLT, EGT - warning above treshold values.
AFR - warning if engine go to lean out above treshold, and skip delay for check after fuelcut and accel enrichment. In AFR (for petrol) values only.
Range could be limited with minrpm and minkpa to prevent blinking (or pain from sound) at street driving, exept overheating, there is no limits for CLT check.