Wow, it really saved my day!!! No whistles at all but very useful.

Woww! close hundreds of tabs with keyword or domain just by typing it in that little box in a fraction of a second!
So useful!
Thanks a lot developer!
For people who complain and want to know how many tabs remaining just install a tab counter like this https://addons.mozilla.org/en-US/firefox/addon/tab-counter-webext/or this https://addons.mozilla.org/en-US/firefox/addon/tab-counter-wide/the later gives you also the position of the active tab
Anyway if you use so many tabs like me (before this add-on more than 1500) you should HAVE a tab counter.
Again, thanks a lot Mosab Ibrahim for this Power Close add-on's gem.

Thanks for the addon, I confirm it works on Firefox Quantom (specifically dev edition v. 65).
But I rate it only 3 stars because there is absolutely no feedback.
I expect to see a list of tabs when I enter the domain name, or at minimum the number of tabs closed.