Describe in model / add operation / XSD purpose of this attribute. It is not obvious from name neither from description "The final name rewriter"

What does this rewriter rewrites?
As a reference, it can be configured in conjuction with pre-realm-mapper and post-realm-mapper, in those two cases I can understand from name and description what is it for.

This JIRA applies to all occurences of final-name-rewriter in model:

• 2x in http-authentication-factory
• 2x in sasl-authentication-factory