Support for XHTML 5 serialization, as defined in the 3.0 Serialization specification,
is available. (Use
<xsl:output method="xhtml" html-version="5.0"/>).
Comments and processing instructions no longer prevent an immediately following start tag being indented if it would have been indented in the absence of the comment or PI.
(However, comments and PIs are not themselves indented, because it is not possible to do this safely without looking ahead to see if the comment or PI is followed by significant character content.)