This example tries to illustrate the XML data model of rrdxport(1), part of the [rrdtool][0] suite. Seems it's not well documented yet. We use [XSLT][1] to print the first and last curves of the model as CSV and the [XPath][2] function format-number() to make the default rrdtool output format for numbers more human readable.
If there is well-formed XML you can run:
xsltproc xport2csv.xsl xport.xml