This Open Packaging specification describes an abstract model and physical format conventions for the use of XML, Unicode, ZIP, and other openly available technologies and specifications to organize the content and resources of a document within a package. It is intended to support the content types and organization for various applications and is written for developers who are building systems that process package content.

In addition, this Open Packaging specification defines common services that can be included in a package, such as Core Properties and Digital Signatures.

A primary goal is to ensure the interoperability of independently created software and hardware systems that produce or consume package content and use common services. This Open Packaging specification defines the formal requirements that producers and consumers shall satisfy in order to achieve interoperability.

Various XML-based building blocks within a package make use of the conventions described in Part 5: “Markup Compatibility and Extensibility” to facilitate future enhancement and extension of XML markup. That part shall be explicitly cited by any markup specification that bases its versioning and extensibility strategy on Markup Compatibility elements and attributes.