"The peak shelf attaches at in the peak of your hammock, 2 D-rings, and your ridgeline to create a nice deep shelf/pocket to store things like jackets and other large gear. This peak shelf can be used for the Chameleon or the Half-Zipped hammock."

 
The above wording is straight from Dutch, and his team. 
 
NB This Chameleon accessory only works with the Dutchware Gear Chameleon Hammocks and not other makes/models.