It think you may misunderstood. I know where they are defined, but I don't know what they are doing. The reference shows custom properties built-in but as mentioned, in this example someone created custom properties which don't come shipped with vCAC.
In this instance I see the properties are defined in build profiles. What I need to find out is where were they created?
Imagine you see a property called
Cake.Baking.Good
Where would you find what it does?
Makes sense ?