title: Bootstrap Offcanvas - do offcanvas css classes really exist?
body: <p>I recently found out about twitter bootstrap and I have been diving deep into the most recent version, Bootstrap 3. On the website, there is an example for an "Off Canvas" template (here: <a href="http://getbootstrap.com/examples/offcanvas/" rel="noreferrer">http://getbootstrap.com/examples/offcanvas/</a> ) which I have been modifying. But there are several things in the example that do not make sense to me.</p>
  
  <p>In the "Off Canvas" template example, there are div elements that reference classes such as "row-offcanvas", "row-offcanvas-right", and "sidebar-offcanvas". I cannot find these in the bootstrap.css, and neither do I see these in the Chrome DevTools. I also do not see any effect when I remove these classes. Do these classes have any purpose? Or was it a mistake in the example to include those seemingly non-existent classes?</p>