Works well, thanks to the developer! I would prefer if left clicking a magnet/torrent would add it without opening transmission web interface. You can avoid this by right clicking magnet/torrent and add it that way, but it's a bit more work.

Works as advertised! The icon could use some work as doesn't really fit in with the new Firefox 57 look, and a tooltip-style "added successfully" notification would be nice, but other than that I'm pretty happy with it. And if you're looking for ideas for version 2, maybe a "sort downloads by ..." option would be nice ;-)

Works OK. Some notification would be needed if adding was successful or otherwise.