Literal comments and processing instructions are also allowed:
<?xml-stylesheet type="application/xml" href="bibliography.css"?>,
<bib>
<h1>Bibliography</h1>
{
for $b in doc("bib.xml")/bib/book
return
$b/title
}
</bib>,
<!-- An example from Elliotte Rusty Harold's
XQuery presentation -->
Remember, an XQuery is not an XML document.