From the source:

/* This is a full featured entitiy fixer.
 * I have to process quite too many defective XML files out there ..
 *
 * This does not fix problems in the XML file structure,
 * however it fixes any problems you might observe with unknown entities.
 * This knows all common HTML entities and transforms them into XML entities.
 * Additionally it knows about double escapes.
 * It also fixes defective escapes (or not escaped & signs).
 *
 * This assumes there are no entities defined in the XML file.
 * Additionally see latin1-utf8.c to fix lazy character encodings.
 *
 * This should be built in xml2sql, as we have access to the known entities there.
 */

Usage:
	entityfix

Notes:
	In case you wonder, " is output as " which is
	correct XML for the quote (") character.  This helps in case
	it happens to show up in the attributes as in:
	<gesture sign="&quot;">Dr. Evil</gesture>
	which is not XML but often mistaken from HTML.  This is
	correctly fixed to
	<gesture sign="&#x22;">Dr. Evil</gesture>
	as
	<gesture sign=""">Dr. Evil</gesture>
	would be complete rubbish. ;)