Coffee ETN questions

What is the iPath® Dow Jones-AIG Coffee Total Return Sub-IndexSM ETN actually linked to: What is the index and what does it track, surely not coffee prices ..

If AIG completely goes under, could a position in this ETN be wiped out?

 

who knows, maybe this is the next GOE

 

Anybody know what's the grade of coffee (robusta, etc) (and market: London? NYC?) that the futures contract in the iPath Dow Jones-AIG Sub IndexSN is linked to, with regard to the JO ETN? I can't believe this information is so hard to find out. I'm fearing there's a reason.