All defined classes, if created with no specified parent class, will
inherit from a special class stored in
eieio-default-superclass. This superclass is quite simple, but
with it, certain default methods or attributes can be added to all
objects. In CLOS, this would be named STANDARD-CLASS, and that
symbol is an alias to eieio-default-superclass.
Currently, the default superclass is defined as follows:
(defclass eieio-default-superclass nil nil "Default parent class for classes with no specified parent class. Its slots are automatically adopted by classes with no specified parents. This class is not stored in the `parent' slot of a class object." :abstract t)
The default superclass implements several methods providing a default behavior for all objects created by EIEIO.