Lists IPTC Application Object Types.
Values:
| IGMDTAG_ID_IPTC_OBJTYPE_NEWS | Object type is News (default). |
| IGMDTAG_ID_IPTC_OBJTYPE_DATA | Object type is Data (intended for tables such as statistics or lists, as opposed to narrative text). |
| IGMDTAG_ID_IPTC_OBJTYPE_ADVISORY | Object type is Advisory (content provider messages, generally not published). |