1. it discovers video stream, but unfortunately sucks in downloading chunked "blob:httрs://..." to a single video file.
2. it's a kinda spamware - contains improve-voice spam with URL to their 30% discount

in general, it tries to do things VLC does best way and without any spam at all

Downloading not possible on youtube it says, it's not a good addon

ダウンロード速度は非常に遅いけれど、他のアドオンではうまくダウンロードできない動画もきっちりダウンロードしてくれます。他のダウンローダーと合わせてインストールしておくと、他のがうまくいかなかった時のフォローができて安心です。

What is the point if it doesn't appear in drop-downs and can't be added to the Toolbar?

Wow...a downloader that actually works.
I tried so many others that don't work at all or they only show a list of small clips of the video, or they require additional software to be installed.
This one shows the full video and the size of the file and downloads fast!....Thanks!

It is no a downloader. Period. I don't know why it need your browsing history. It is just a dangerous add-on.

Not working.