<xsl:template>

The <xsl:template> element defines an output producing template. This element must have either the match attribute or the name attribute set.

xml

<xsl:template
  match=PATTERN
  name=NAME
  mode=NAME
  priority=NUMBER>
  <xsl:param> [optional]
  TEMPLATE
</xsl:template>

None.

match: Specifies a pattern that determines the elements for which this template should be used. It is a required attribute if there is no name attribute.
name: Specifies a name for this template, by which it can be invoked through the <xsl:call-template> element.
mode: Specifies a particular mode for this template, which can be matched by an attribute of the <xsl:apply-templates> element. This is useful for processing the same information in multiple ways.
priority: Specifies a numeric priority for this template. This can be any number other than Infinity. The processor uses this number when more than one template matches the same node.

Top-level, must be the child of <xsl:stylesheet> or <xsl:transform>.

XSLT, section 5.3.

Supported.