What's "EGS"?

[wade]

EGR - Exhaust Gas Recirculation System
FI - Fuel Injection
TWC - Three-Way Catalyst
EGS - ???

I can't find a definition for EGS. I think it has something to do with the Ignition System, but not sure?
Can anyone help? (see the bottom of the pic)

 

[V8 Level II]

EGS = Exhaust Gas Sensor (AKA Oxygen Sensor)