From Here: http://www.ktm950.info/how/wotf/wotf.html#LowOctanePlug
Low Octane Plug:
The LC8 engine in the 950/990 KTM Adventures and Super Enduros line have an 11.5:1 compression ratio. It is designed to run on 95 RON premium fuel. The equivilent octane in the USA is 91 octane (RON+MON)/2. KTM thoughtfully provided a wire under the seat that can be disconnected when the high octane stuff isn't available. It causes the ECU to select a less aggressive ignition advance curve to prevent preignition. It is supposed to be good for down to 80 RON (77 in the USA).
KTM specifies that only one tank of low octane fuel be used at a time. ie: this is supposed to be for emergency use only. Not for a way to run less expensive gas as a routine.