What's this torque specification on the seatpost for? I read 12Nm torque on my seatpost (a Cinelli Vai seatpost).

What does this torque refer to?

I would assume it's for the two bolts above that tie the saddle rail to the seatpost, but at the same time it looks like a very high torque to me for those bolts, so I am confused.
I suggest looking at this table from Park Tool for what each component needs for torque. 

For the seat rail binder (aka seat fixing bolt aka the bolts you've photographed), Park tool gives a range from 174 - 347 in-lbs as the Shimano value, with some others requiring as little as 44 or others as much as 300. 

If we convert 174 in-lbs to N-m, thats about 20 N-m (the rule is divide by 9-ish). So, its a reasonable value for the bolts under question. 

As noted in the table, the number doesn't really make sense for the seatpost binder (thing that holds the seatpost in the frame); you normally just go enough that it doesn't slip for that, which Campy suggests 4-6 N-m which is much lower.



All being said, I'm not sure who actually measures that torque unless you have fragile saddle rails or post or something. But I suspect many people go (well) below the 20 Nm ish figure from Park Tool by a good amount. I've never used a torque wrench for this,  but I'd guess I've tightened with 10 Nm at best.