--- title: Theme Packaging slug: Theme_Packaging tags: - Themes - Toolkit API translation_of: Mozilla/Thunderbird/Thunderbird_extensions/Theme_Packaging ---

This document describes how to package themes for Firefox and Thunderbird.

Note: This article is out of date, in that it still talks about the contents.rdf file, which has been deprecated since Gecko 1.8, and is no longer supported starting with Gecko 1.9.2. You must use the chrome.manifest method for registering chrome to be forward compatible. It would be greatly appreciated if someone with theming experience could work on an update to this article.

Pre-requisites

Making a theme for Firefox or Thunderbird requires knowledge of Cascading Stylesheets (CSS), probably XBL, and some graphic design and aesthetic skill (...or maybe not). This document describes only how Themes are packaged in order to be shown in Firefox's Themes window.

Theme File Layout

Firefox/Thunderbird themes are packaged in a JAR file with the following structure:

theme.jar:
  install.rdf
  contents.rdf
  preview.png
  icon.png
  browser/files
  global/files
  mozapps/files
  communicator/files
  ...

You must have a top-level chrome.manifest (Firefox/Thunderbird 1.5) or contents.rdf file which registers the chrome for the theme (as before) and also an install.rdf manifest that specifies metadata that is displayed in the Themes window.
preview.png is a preview image which will show in the scrolling preview area in the Themes window. It can be any size.
icon.png is a 32x32 PNG (may contain alpha transparency) which will show up in the Themes list in the Themes window.

install.rdf

Your install.rdf manifest will look something like this:

<?xml version="1.0"?>

<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:type>4</em:type>more properties
  </Description>
</RDF>

Required install.rdf Properties

Your install.rdf file must have the following properties. See the install.rdf Reference for more information:

em:id
em:version
em:type
em:targetApplication
em:name
em:internalName

Optional install.rdf Properties

em:description
em:creator
em:contributor
em:homepageURL
em:updateURL

Note that if your theme will be made available on the http://addons.mozilla.org website, it should not include an updateURL.

Sample install.rdf File

<?xml version="1.0"?>

<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>{18b64b56-d42f-428d-a88c-baa413bc413f}</em:id>
    <em:version>1.0</em:version>
    <em:type>4</em:type>

    <!-- Target Application this extension can install into,
         with minimum and maximum supported versions. -->
    <em:targetApplication>
      <Description>
        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
        <em:minVersion>0.8</em:minVersion>
        <em:maxVersion>0.9</em:maxVersion>
      </Description>
    </em:targetApplication>

    <!-- Front End MetaData -->
    <em:name>New Theme 1</em:name>
    <em:description>A test theme for Firefox</em:description>
    <em:creator>Ben Goodger</em:creator>
    <em:contributor>John Doe</em:contributor>
    <em:homepageURL>http://www.bengoodger.com/</em:homepageURL>

    <!-- Front End Integration Hooks (used by Theme Manager)-->
    <em:internalName>newtheme1</em:internalName>
  </Description>
</RDF>

The following are some common target application GUIDs that you can use in your targetApplication properties: