2.1.28 Part 1 Section 15.2.5, Custom XML Data Storage Part

a.   The standard does not specify that Office reserves namespaces for storing document properties.

Office reserves the following specific namespaces for storing document properties:

Root Namespace	Reference
http://schemas.microsoft.com/office/2006/customDocumentInformationPanel	§3.5.3.1, Custom Document Information Panel Schema
http://schemas.microsoft.com/office/2006/metadata/customXsn	§3.5.4.1, Custom XSN Schema
http://schemas.microsoft.com/office/2006/metadata/contentType	§3.5.2.1, Content Type Schemas Schema
http://schemas.microsoft.com/office/2006/coverPageProps	§3.5.1.1, Cover Page Properties Schema
http://schemas.microsoft.com/office/2006/metadata/longProperties	§3.5.5.1, Long Properties Schema
office.server.policy	Collaborative Application Markup Language (CAML) Structure Specification ([MS-WSSCAML] Subclause 2.5.1.7).

Furthermore, a Custom XML Data Storage part with root namespace of http://schemas.microsoft.com/office/2006/metadata/properties describes the properties of this document as defined by the xsd:schema children of Content Type Schemas (§3.5.2.1, Content Type Schemas Schema). The xsd:schema that bears the ma:root Root (§3.5.2.2.1, Shared Attributes) attribute describes the structure of the root element this Custom XML Data Storage part, with the other xsd:schema children collectively describing elements from other namespaces referenced.