About the XML namespace This schema document describes the XML namespace, in a form suitable for import by other schema documents. »

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.

id (as an attribute name) denotes an attribute whose value should be interpreted as if declared to be of type ID.

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.

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.