endnotes.heading.style — Style of the heading of endnotes groups
<xsl:param name="endnotes.heading.style" select="'select:title'"/>
This parameter is provided to format the heading of an endnote group.
It uses the xrefstyle syntax, and therefore one can
specify directly a template, or select some keywords to substitute.
For more details see the section called “Grouping Endnotes”.