<varlistentry id="docguide-toolsets-docbook-xsl">
     <term><ulink url="https://github.com/docbook/wiki/wiki/DocBookXslStylesheets">DocBook XSL Stylesheets</ulink></term>
     <listitem>
      <para>
       These contain the processing instructions for converting the
       DocBook sources to other formats, such as
       <acronym>HTML</acronym>.
      </para>

      <para>
       The minimum required version is currently 1.77.0, but it is recommended
       to use the latest available version for best results.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="docguide-toolsets-libxml2">
     <term><ulink url="http://xmlsoft.org/">Libxml2</ulink> for <command>xmllint</command></term>
     <listitem>
      <para>
       This library and the <command>xmllint</command> tool it contains are
       used for processing XML.  Many developers will already
       have <application>Libxml2</application> installed, because it is also
       used when building the PostgreSQL code.  Note, however,
       that <command>xmllint</command> might need to be installed from a
       separate subpackage.
      </para>
     </listitem>
     </varlistentry>

    <varlistentry id="docguide-toolsets-libxslt">
     <term><ulink url="http://xmlsoft.org/XSLT/">Libxslt</ulink> for <command>xsltproc</command></term>
     <listitem>
      <para>
       <command>xsltproc</command> is an XSLT processor, that is, a program to
       convert XML to other formats using XSLT stylesheets.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry id="docguide-toolsets-fop">
     <term><ulink url="https://xmlgraphics.apache.org/fop/">FOP</ulink></term>
     <listitem>
      <para>
       This is a program for converting, among other things, XML to PDF.
       It is needed only if you want to build the documentation in PDF format.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

  <para>
   We have documented experience with several installation methods for
   the various tools that are needed to process the documentation.
   These will be described below.  There might be some other packaged
   distributions for these tools. Please report package status to the
   documentation mailing list, and we will include that information
   here.
  </para>

  <sect2 id="docguide-toolsets-inst-fedora-et-al">
   <title>Installation on Fedora, RHEL, and Derivatives</title>

   <para>
    To install the required packages, use:
<programlisting>
yum install docbook-dtds docbook-style-xsl libxslt fop
</programlisting>
   </para>
  </sect2>

  <sect2 id="docguide-toolsets-inst-freebsd">
   <title>Installation on FreeBSD</title>

   <para>
    To install the required packages with <command>pkg</command>, use:
<programlisting>
pkg install docbook-xml docbook-xsl libxslt fop
</programlisting>
   </para>

   <para>
    When building the documentation from the <filename>doc</filename>
    directory you'll need to use <command>gmake</command>, because the
    makefile provided is not suitable for FreeBSD's <command>make</command>.
   </para>
  </sect2>

  <sect2 id="docguide-toolsets-inst-debian">
   <title>Debian Packages</title>

   <para>
    There is a full set of packages of the documentation tools
    available for <productname>Debian GNU/Linux</productname>.
    To install, simply use:
<programlisting>
apt-get install docbook-xml docbook-xsl libxml2-utils xsltproc fop
</programlisting>
   </para>
  </sect2>

  <sect2 id="docguide-toolsets-inst-macos">
   <title>macOS</title>

   <para>
    If you use MacPorts, the following will get you set up:
<programlisting>
sudo port install docbook-xml docbook-xsl-nons libxslt fop
</programlisting>
    If you use Homebrew, use this:
<programlisting>
brew install docbook docbook-xsl libxslt fop
</programlisting>
   </para>

   <para>
    The Homebrew-supplied programs require the following environment variable
    to be set.  For Intel based machines, use this:
<programlisting>
export