title: Firefox Addon - install.rdf - What does the "em" mean in <em:description>...</em:description>
body: <p>What does the <code>em</code> mean in    </p>
  
  <pre><code>&lt;em:description&gt;...&lt;/em:description&gt;
  </code></pre>
  
  <p>This is an extract from a firefox addon <code>install.rdf</code> file. I am curious as to what the <code>em</code> part adds to this. I could not find a solution to this on Google either.</p>