My V6 '14 Limited just has the simple "ECO" button (which I hope stands for "Economy" not "Eco-friendly"). It shows an amber light when it is turned on... which is the automatic default setting.
The manual shows a fancier button with a pretty pictogram of a fuel pump and a leaf on it. Plus the description sound like it's default setting should be off. Perhaps this is what comes on the V8, Diesel, or Overland and above models.
It bugs me that the ECO is default on. It really degrades the performance of the JGC and, best as I can tell, doesn't really help w/ the mileage. Plus, if I really cared about fuel economy I wouldn't have bought a JGC in the first place.