The “uri” entry maps one URI to another.
<uri name="http://docbook.org/rng/4.2/docbook.rng"
uri="schema/relaxng/docbook.rng"/>
<uri name="http://docbook.sf.net/xsl/fo/docbook.xsl"
uri="xsl/fo/docbook.xsl"/>
<uri name="http://docbook.sf.net/bibl/bibl.xml"
uri="file:/home/ndw/.bibliography.xml"/>
<uri name="http://docbook.sf.net/images/draft.png"
uri="xsl/images/draft.png"/>