XMLEscaping specifies whether responses
are XML-encoded in a single pass or a double pass. By default,
XMLEscaping is
"Single," and Product Advertising API
responses are encoded only once in XML. For example, if the
response data includes an ampersand character (&), the
character is returned in its regular XML encoding (&).
If XMLEscaping is
"Double," the same ampersand character is
XML-encoded twice (&). The Double value for
XMLEscaping is useful in some
clients, such as PHP, that do not decode text within XML
elements.