Location module.

Content-Transfer-Encoding value

Content-type module.

This module provides an alternative to Unstructured which handles encoded words. It is meant for the Subject and other unstructured header fields, where RFC-2047 adds additional semantics on top of the SMTP protocol. The addition of encoded words allows sending UTF-8 content in a 7 bit protocol, like SMTP without the SMTPUTF8 extension.