Addon lets unload tabs, all tabs, just one click.
Good radical resolution for firefox' craving for all your RAM.

Some bug:
A fresh install of addon after activating unloading, it displays notification with number of unloaded tabs. This number is incorrectly only counting tabs loaded after installation of addon. These tabs also get a tick mark in tab row.
Though all tabs get unloaded.

I dislike its permission to "Access your data for all websites".

Addon unsolicitedly loads its homepage after installation and after uninstallation. Submits extra data in URL. Homepage shows advertisement. So one can argue that addon is advertising. Though ads were for other addons on homepage.

A little bit too agressive with inactive tabs, especially those who are playing a media...
However, It make the job.