Missing XSL snippets

Many snippets from Emmet cheatsheet are missing from default settings. E.g. xsl snippet is supposed to expand into

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
</xsl:stylesheet>

but it's not present in configuration.