FrenchRestaurantTable Sample Project

Hi, I was breaking down layers from a sample project, FrenchRestaurantTable one by one, so that I can learn how to work efficiently and possibly new fuctions from it. 

And While I was looking at it, I found that there is a AO brightening layers which they are getting resource information from Shape for mask. And I wonder what it is. and possibly how I can apply this to my work. 

Thanks!