gecko-dev/extensions/inspector/install.rdf

<?xml version="1.0"?>

#filter substitution

<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
  <Description about="urn:mozilla:install-manifest">
    <em:id>inspector@mozilla.org</em:id>
    <em:version>@EXTENSION_VERSION@</em:version>

    <em:targetApplication>
      <!-- Firefox -->
      <Description>
        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
        <em:minVersion>@FIREFOX_VERSION@</em:minVersion>
        <em:maxVersion>@FIREFOX_VERSION@</em:maxVersion>
      </Description>
    </em:targetApplication>

    <em:targetApplication>
      <!-- Thunderbird -->
      <Description>
        <em:id>{3550f703-e582-4d05-9a08-453d09bdfdc6}</em:id>
        <em:minVersion>@THUNDERBIRD_VERSION@</em:minVersion>
        <em:maxVersion>@THUNDERBIRD_VERSION@</em:maxVersion>
      </Description>
    </em:targetApplication>
    
    <!-- EXTENSION AUTHORS!
         DO NOT COPY THIS PROPERTY INTO YOUR INSTALL RDF FILES
         It will cause users not to be informed of incompatibilities 
         with your extension when they are updated with Software Update
         and your extension will become unavailable to them!
         -->
    <em:appManaged>true</em:appManaged>

    <!-- front-end metadata -->
    <em:name>DOM Inspector</em:name>
    <em:description>Inspect the DOM of HTML, XUL, and XML pages, including the browser chrome.</em:description>
    <em:creator>mozilla.org</em:creator>
    <em:homepageURL>http://www.mozilla.org/projects/inspector/</em:homepageURL>
  </Description>
</RDF>