title: Find out the path to the addon folder in the Thunderbird API
body: <p>I am modifying an addon for thunderbird and found the path to the addon hardcoded in one of the javascript files. This seemed sloppy to me and I thought that it had to be possible to find out this path programmatically. However, after much googeling, I still can't find an answer to that question.</p>
  
  <p>Do you know how I can find out the path to the folder (containing the <code>install.rdf</code>) of a Thunderbird addon? </p>