It's just taking the part after chicane a bit wide to the right. Gains you a whole sec at least. (Yea, that's my lap there on the list).
I don't think that the Abarth on Vallelunga is an exploitable laptime, on instance. I would love to see those 1.31s there though. I mean, on youtube they didn't really look that fast, I'm still half a second off that though.