XML or eXtensible Markup Language is used in different places in Automation Engine. XPath is a query language that allows to retrieve data elements from a XML document.
W3 schools is a good starting point.
The XML tutorial can be found here: http://www.w3schools.com/xml/default.asp.
The XPath tutorial can be found here: http://en.wikipedia.org/wiki/XPath.
Automation Engine all versions
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