Tahoe-LAFS Indicator/StatusIcon
sudo add-apt-repository ppa:rubiojr/tahoe-lafs && sudo apt-get update
sudo apt-get install tahoe-lafs-indicator
By default, the indicator checks http://localhost:3456, which is the default URL. There's no GUI to configure it yet so, if you need to change it, edit ~/.config/tahoetray/settings.yaml