`<xref/>` to `<procedure>` ignores localized context override in DocBook XSLT 1.0

[tomschr]

Situation

When using DocBook 5 with the DocBook XSLT 1.0 stylesheets (XHTML output), a localized context override for the element name procedure is honored for titles, but ignored for <xref/> resolution.

This occurs when you customize the term "Procedure" for German and want to replace it by "Vorgehen". I think, the issue appears for other language as well.

Environment

• DocBook: 5.2
• Stylesheets: DocBook XSLT 1.0 (namespaced, XHTML) 1.79.2
• Processor: xsltproc
• Output format: XHTML
• Language: German (xml:lang="de")

Proof-of-concept

Here are the example files shown this problem for a German document:

Article (article.xml)

<article xml:lang="de" version="5.2"
  xmlns="http://docbook.org/ns/docbook"
  xmlns:xlink="http://www.w3.org/1999/xlink">
  
  <title>Beispielartikel</title>
  
  <para>
    Siehe <xref linkend="proc.install"/>.
  </para>
  
  <procedure xml:id="proc.install">
    <title>Installation durchführen</title>
    
    <step>
      <para>Paket herunterladen.</para>
    </step>
    
    <step>
      <para>Paket installieren.</para>
    </step>
  </procedure>
  
</article>

Language file (l10n.xml)

<l:i18n xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0">
  <l:l10n language="de" english-language-name="German">
    <l:gentext key="Procedure" text="Vorgehen"/>
    <l:gentext key="procedure" text="Vorgehen"/>
    
    <l:context name="title">
      <l:template name="procedure.formal" text="Vorgehen %n. %t"/>
    </l:context>

    <l:context name="xref-number">
      <l:template name="procedure" text="Vorgehen %n"/>
    </l:context>

    <l:context name="xref-number-and-title">
      <l:template name="procedure.formal" text="Vorgehen %n. %t"/>
    </l:context>
  </l:l10n>
</l:i18n>

Stylesheet (db2xhtml.xsl)

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

  <xsl:import href="http://docbook.sourceforge.net/release/xsl-ns/current/xhtml5/docbook.xsl"/>

  <xsl:param name="local.l10n.xml" select="document('l10n.xml')"/>

</xsl:stylesheet>

Store everything in one directory and call this command:

xsltproc --output article.html db2xhtml.xsl article.xml

The result is this:

Expected Result

The <xref/> text should use the customized language context for procedure, for example.:

Siehe Vorgehen 1, „Installation durchführen“.

Analysis / Notes

• The custom localization is correctly loaded and applied (verified via title output).
• The issue appears specific to <procedure> and <xref/>.
• It seems that, in DocBook XSLT 1.0, <xref/> to procedure does not consult gentext with context xref, but instead falls back to a hard-coded localized object name.
• This makes it impossible to fully localize procedure references via local.l10n.xml alone.