1.5    Document Processing and Conformance

Documents that conform to the OpenDocument specification may contain elements and attributes not specified within the OpenDocument schema. Such elements and attributes must not be part of a namespace that is defined within this specification and are called foreign elements and attributes.

Conforming applications either shall read documents that are valid against the OpenDocument schema if all foreign elements and attributes are removed before validation takes place, or shall write documents that are valid against the OpenDocument schema if all foreign elements and attributes are removed before validation takes place.

Conforming applications that read and write documents may preserve foreign elements and attributes.

In addition to this, conforming applications should preserve meta information and the content of styles. This means:

�        The various <style:*-properties> elements (see section 15) may have arbitrary attributes attached and may have arbitrary element content. All attributes attached to these elements and elements contained within these elements should be preserved (see section 15.1.3);

�        elements contained within the <office:meta> element may have arbitrary element content and should be preserved (see section 2.2.1).

Foreign elements may have an office:process-content attribute attached that has the value true or false. If the attribute's value is true, or if the attribute does not exist, the element's content should be processed by conforming applications. Otherwise conforming applications should not process the element's content, but may only preserve its content. If the element's content should be processed, the document itself shall be valid against the OpenDocument schema if the unknown element is replaced with its content only.

Conforming applications shall read documents containing processing instructions and should preserve them.

There are no rules regarding the elements and attributes that actually have to be supported by conforming applications, except that applications should not use foreign elements and attributes for features defined in the OpenDocument schema. See also appendix D.