Can someone explain this xml mapping please

Hello SAP PI Experts,

Below I have provided a mapping program I found. It is for an IDoc to IDoc scenario. Kindly explain how the fields are mapped here.

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:output method="xml" version="1.0" indent="yes"  encoding="ISO-8859-1"/>

  <xsl:template match="/">

  <xsl:copy-of select="*"/>

  </xsl:template>

</xsl:stylesheet>

Thanks,

Ajeya G V