Extension instructions
A Saxon extension instruction is invoked using a name such as <saxon:localname>.
The saxon prefix (or whatever prefix you choose to use) must be associated with the
Saxon namespace URI http://saxon.sf.net/. The prefix must also be designated as an
extension element prefix by including it in the
extension-element-prefixes attribute on the xsl:stylesheet element, or the
xsl:extension-element-prefixes attribute on any enclosing literal result element or
extension element.
However, top-level elements such as saxon:collation and
saxon:script can be used without
designating the prefix as an extension element prefix.
The extension instructions and declarations are: