This schema defines elements and attributes for Office Open XML markup compatibility. Specifies which prefixes should be ignored if they are not recognized. Specifies which prefixes should have their content processed. Specifies which prefixes must be understood for proper interpretation. Container for alternative content based on markup compatibility. Alternative content choice based on namespace support. Specifies which namespace prefixes must be understood for this choice to be selected. Fallback content when no Choice element's requirements are met.