What does this mean in used car adverts?

[jhiker]

Quick question re: gearboxes: what does ‘Euro 6 (s/s)’ and ‘Step Auto’ refer to on Autotrader adverts for 320i petrol/auto?

[Zarco]

S/S is stop/start.

Not sure about the other one.

[_Hoppers]

https://www.bmwoffreeport.com/blogs/827/the-bmw-st...

[ShinyPsyduck]

Start/Stop and "The BMW's Steptronic automatic transmission gives you options so that you don't have to choose between an automatic or manual transmission. The gearbox with the Steptronic gives you a choice between using a manual shift when you want to and changing over to the multi-drive mode automatic when you need it.2 Sept 2021"

I googled the last one.