If it is anything like the older Z's:
From my 2017 Z8 wiring diagram ...
That's the Ignition Signal line (15amps?). If that fuse blows, then no power gets to the engine kill switch, Fuel pump, EFI System, Starter relay, and it behave just as if the kill switch was on.
Of course, a Z950 wiring diagram would be a better resource.