Appendix B -- Advanced DXF Issues
Extension Dictionary and Persistent Reactors

The extension dictionary is an optional sequence that stores the handle of a dictionary object that belongs to the current object, which in turn may contain entries. This facility allows attachment of arbitrary database objects to any database object. Any object or entity may have this section.

Persistent reactors are an optional sequence that stores object handles of objects registering themselves as reactors on the current object. Any object or entity may have this section.