base.xsd Some base components required in various places in XMML Copyright © 2005 CSIRO - see https://www.seegrid.csiro.au/twiki/bin/view/Xmml/LegalNotices#Software_Notice mixed="false", so this can serve as the basis for element-only MetaData elements Vacuous extension of a mixed type, resulting in just a text element. For unstructured metadata. A place to attach components that are required to be listed someplace in order that they can be "used" by-reference elsewhere in (usually) the same instance document. Container for commentary that may not be strictly part of a "description". Description of geographic location or extent using an identifier