This is the default traits class for the intersection algorithms for iso-oriented boxes. There are actually three versions depending on the type of BoxHandle; there is one if BoxHandle is a class type and there are two if BoxHandle is a pointer type, one for a mutable and one for a const pointer, respectively.
This class implements the mapping from its BoxHandle argument to the Box_parameter type required in the BoxIntersectionTraits_d concept. In particular in the case where BoxHandle is a class type B, it defines Box_parameter to be of type const B&, while for the other cases it just uses the pointer type.
and also automatically with