Unfortunately, since the author has completely dropped support, this is soo buggy that I would warn anyone to NOT install it at all. You will get script errors on any webpage load, to the point that you are closing an error page, sometimes multiple times per page, each and every time you open a new page.
The update to version 35 messed up my firefox because of this extension. Selecting a tab containing a webpage an error dialog appears. Every time. Then arbitrarily the tab is moved to a new window. Here is a screenshot: http://i0.simplest-image-hosting.net/picture/finestra-e-errore.png I think the problem is easily reproducible. This is a useful extension, please fix it.
Let me try to clarify the situation. Today, modern versions of apache/ngnix servers (alas, doesn't refer to my ISP;) show http-directories in a pretty humanistic form (see for ex. http://ftp.mozilla.org/pub/mozilla.org) -- so the plugin doesn't understand this new-fashion format, however, it becomes needless for such up-to-date websites. —— in conclusion, it's a pity that the author ceased the maintenance of his chef-d'oeuvre :(
I love this add-on and have been using it contently for a very long time already. However, newer versions (1.2.9 and newer) introduced a small bug with certain webpages (@ www.marktplaats.nl). I have been unable to contact the author since the e-mail address seems to be invalid. (host unavailable or maybe domain name expired?) Luckily I could revert back to 1.2.7. Currently I'm using Firefox 4 beta 9.