| msg_accept_any_s | Structure for Accept-Charset, Accept-Encoding and Accept-Language headers |
| msg_accept_s | Structure for Accept header |
| msg_auth_info_s | Authentication-Info header |
| msg_auth_s | Authentication header |
| msg_buffer_s | Buffer for message body |
| msg_common_s | Common part of the header objects (or message fragments) |
| msg_content_disposition_s | Structure for Content-Disposition header |
| msg_content_length_s | Structure for Content-Length header |
| msg_content_type_s | Structure for Content-Type header |
| msg_error_s | Erroneus header |
| msg_generic_s | Generic header |
| msg_hclass_s | Factory object for a header |
| msg_header_u | Any header |
| msg_href_s | Header reference |
| msg_list_s | List header |
| msg_mclass_s | Factory object for protocol messages |
| msg_multipart_s | Structure for a part in MIME multipart message |
| msg_numeric_s | Numeric header |
| msg_payload_s | Message payload |
| msg_pub_s | Message object, common view |
| msg_s | Message object |
| msg_separator_s | Separator |
| msg_unknown_s | Unknown header |
| msg_warning_s | Structure for Warning header |
