It's a digital tome designed to guide players through DOTA 2's tournaments, as well as letting them participate in related events. 25% of proceeds go into the prize pool.
This is the second stretch goal achieved by the community buying these International Interactive Compendiums, which has added over $250k to the International Prize Pool.
"Our original plan was for the International 2013 Courier to be able to ride a small set of mounts, and now the art team knows the community demands more," Valve.
"Given how much faster the community is reaching the stretch goals we set up, we’ve decided to add some more, based on the many conversations we’ve seen the community having around the compendium." More details about the next stretch goal are due soon. The first stretch goal was a Battle Bonus that improved Battle Point earnings.