很好用，谢谢，是我想要的功能

Good

Excellent! A must have for me.

good

Полезное дополнение

Just great, allow to check what an extension does before dowloading and install it (well, if you now about coding...).
It should be followed and recommanded by Mozilla !!!

I agree with another comment: it would be great if could show addon-UID.
Thank you to the developper, who to care of answering to the other comment and provided an easy way to get thins info: go to address about:support and see below "Extensions"