This schema defines attributes and an attribute group that enable schemas such as the ETSI TS 102 822-3-1 V1.3.1 (2005-06) metadata schema and schemas derived from it to allow xml:base, xml:lang or xml:space attributes on elements they define. See http://www.w3.org/XML/1998/namespace.html and http://www.w3.org/TR/REC-xml for information about this namespace. This schema document describes the XML namespace, in a form suitable for import by other schema documents. Note that local names in this namespace are intended to be defined only by the World Wide Web Consortium or its subgroups. The following names are currently defined in this namespace and should not be used with conflicting semantics by any Working Group, specification, or document instance: base (as an attribute name): denotes an attribute whose value provides a URI to be used as the base for interpreting any relative URIs in the scope of the element on which it appears; its value is inherited. This name is reserved by virtue of its definition in the XML Base specification. lang (as an attribute name): denotes an attribute whose value is a language code for the natural language of the content of any element; its value is inherited. This name is reserved by virtue of its definition in the XML specification. space (as an attribute name): denotes an attribute whose value is a keyword indicating what whitespace processing discipline is intended for the content of the element; its value is inherited. This name is reserved by virtue of its definition in the XML specification. This schema defines attributes and an attribute group suitable for use by schemas wishing to allow xml:base, xml:lang or xml:space attributes on elements they define. To enable this, such a schema must import this schema for the XML namespace, e.g. as follows: <schema . . .> . . . <import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd"/> Subsequently, qualified reference to any of the attributes or the group defined below will have the desired effect, e.g. <type . . .> . . . <attributeGroup ref="xml:specialAttrs"/> will define a type which will schema-validate an instance element with any of those attributes In keeping with the XML Schema WG's standard versioning policy, this schema document will persist at http://www.w3.org/2004/10/xml.xsd. At the date of issue it can also be found at http://www.w3.org/2001/xml.xsd. The schema document at that URI may however change in the future, in order to remain compatible with the latest version of XML Schema itself, or with the XML namespace itself. In other words, if the XML Schema or XML namespaces change, the version of this document at http://www.w3.org/2001/xml.xsd will change accordingly; the version at http://www.w3.org/2004/10/xml.xsd will not change. Attempting to install the relevant ISO 2- and 3-letter codes as the enumerated possible values is probably never going to be a realistic possibility. See RFC 3066 at http://www.ietf.org/rfc/rfc3066.txt and the IANA registry at http://www.iana.org/assignments/lang-tag-apps.htm for further information. See http://www.w3.org/TR/xmlbase/ for information about this attribute.