An example identity transform XSLT stylesheet

identity-transform.xsl

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:tei="http://www.tei-c.org/ns/1.0"
    xmlns="http://www.tei-c.org/ns/1.0"
    xpath-default-namespace="http://www.tei-c.org/ns/1.0"
    exclude-result-prefixes="xs tei"
    version="2.0">
    
    <!-- Notice TEI namespace is also given in 'xpath-default-namespace' -->
    
<!-- 
 Basic Identity Transform Example
 Date: 2020-04-30
 By: James Cummings
 License: CC+BY
    -->
    
    <!-- Indent output -->
    <xsl:output indent="yes"/>
    
    <!-- Copy all input to output except below -->
    <xsl:template match="@*|node()" mode="#all">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()" mode="#current"/>
        </xsl:copy>
    </xsl:template>
    
    
    <!-- Copy divs but add numbered @xml:id -->    
    <xsl:template match="body/div">
        <xsl:variable name="num"><xsl:number count="div" level="any" from="body"/></xsl:variable>
        <xsl:copy>
            <xsl:attribute name="xml:id"><xsl:value-of select="concat('div', $num)"/></xsl:attribute>
            <xsl:apply-templates select="@*[not(name()='xml:id')]|node()"/>
        </xsl:copy>
       </xsl:template>
    
</xsl:stylesheet>