chrome/common/extensions/docs/templates/articles/linux_hosting.html

<h1>Hosting for Linux</h1>

<p>
  Extensions hosted on a server outside of the
  <a href="http://chrome.google.com/webstore">Chrome Web Store</a>
  can only be installed by Linux users.
  This page describes how to serve <code>.crx</code> files
  from a personal server.
  If distributing an extension or theme solely through the
  <a href="http://chrome.google.com/webstore">Chrome Web Store</a>,
  consult the <a href="/webstore">store developer documentation</a>.
</p>

<p>
  Extensions and themes are served as <code>.crx</code> files.
  When uploading through the
  <a href="https://chrome.google.com/webstore/developer/dashboard">Chrome Developer Dashboard</a>,
  the dashboard creates the <code>.crx</code> file automatically.
  If published on a personal server,
  the <code>.crx</code> file will need to be created locally,
  as described in <a href="packaging">Packaging</a>.
  <a href="autoupdate">Autoupdate</a> information can be included
  to ensure users always have the latest copy.
</p>

<p>
  A server that hosts <code>.crx</code> files
  must use appropriate HTTP headers,
  so that users can install the file
  by clicking a link to it.
</p>

<p>
  Google Chrome considers a file to be installable
  if <b>either</b> of the following is true:
</p>

<ul>
  <li>
    The file has the content type
    <code>application/x-chrome-extension</code>
  </li>
  <li>
    The file suffix is <code>.crx</code>
    and <b>both</b> of the following are true:
    <ul>
      <li>
        The file <b>is not</b> served with
        the HTTP header <code>X-Content-Type-Options: nosniff</code>
      </li>
      <li>
        The file <b>is</b> served
        with one of the following content types:
        <ul>
          <li> empty string </li>
          <li> "text/plain" </li>
          <li> "application/octet-stream" </li>
          <li> "unknown/unknown" </li>
          <li> "application/unknown" </li>
          <li> "*/*" </li>
        </ul>
      </li>
    </ul>
  </li>
</ul>

<p>
  The most common reason for failing to recognize an installable file
  is that the server sends the header
  <code>X-Content-Type-Options: nosniff</code>.
  The second most common reason
  is that the server sends an unknown content type&mdash;one
  that isn't in the previous list.
  To fix an HTTP header issue,
  either change the configuration of the server
  or try hosting the <code>.crx</code> file at another server.
</p>