Class::Accessor::Class provides a simple way to create accessor and mutator
methods for class variables, just as Class::Accessor provides for objects.
It can use either an enclosed lexical variable, or a package variable.

This module was once implemented in terms of Class::Accessor, but changes
to that module broke this relationship. Class::Accessor::Class is still a
subclass of Class::Accessor, strictly for historical reasons. As a side
benefit, a class that isa Class::Accessor::Class is also a Class::Accessor
and can use its methods.