This is quite useful and, even though there is the occasional glitch requiring reloading the page or clearing the cache, I think it's worth the 5 stars (and a contribution!).

I would like to see a more detailed description of just how the download takes place (I may unpack the xpi and take a peek).

Update: I had a glitch and contacted the developer - and got a very quick and helpful response. This addon is definitely worth supporting.

And another update: once again I needed to contact the developer and received very, very quick turnaround with helpful information. This add-on has been very useful to me for a number of years now.