use "Downr YouTube Downloader" instead. Search for it in addon store.

addons.mozilla.org/en-US/firefox/addon/downr-youtube-downloader/

not working

Não funcionou.

看其他評論好像是現在不能用了，的確不能用。

Could not extract signature deciphering actions, sadly doesn't work anymore.

it used to work but not any more so sad to see this go

Hasn't worked in ages.

Has been a really great addon for a long time until it stopped working for me three years ago.
So I did let it live in my firefox out of hope that someday there may be an update which would get it working again.

But I think after three years of waiting in vain, it's safe to pronounce this add-on dead, uninstall it and look for alternatives.

So long, and thanks for all the videos, but I guess it's time to move on.

I was shocked to see that this was still installed. No buttons have shown up for years. It's a totally broken mess that i'm, about to remove.

This was the best youtube downloader available but it no longer works and it appears the developer has given up as no updates for 3 years.

This is pure garbage, not working at all!

更新もないようなので移行します。