Book: Security architecture in revision 864568d5
Section: 2.6.1.10. REALM MAPPERS

Issue description:
Description of Realm mappers says that they are associated with security domain. However they can be also associated with mechanism or mechanism-realm of http-authentication-factory and sasl-authentication-factory.

Suggestion for improvement:
Add information that Realm mappers can be also associated with mechanism or mechanism-realm of http-authentication-factory and sasl-authentication-factory.