The only thing I can find is Society of Software Engineers. I bought the car in Tampa at a Mercedes dealership. When the car was registered to the Tesla App it comes up as SSE. The Tesla store told me it was unusual to come across a tesla which has Beta showing on the screen. I put the VIN number in at tesla and it came up on the App as SSE. it has enhanced auto pilot, summon & autosteer. It shows (Beta) next to each item. The car drives itself, changes lanes, stops, it does it all and I'm a bit over the top at how wonderful an experience it is to be inside it. I haven't felt this way about a car since I was 17 and got my first beater. In any event, any help knowing what the SSE means would be helpful. Thanks!