Dec. 28, 2019 - I have to agree with many other users - this extension does not "see" videos and cannot download anything. I went with the addon from VideoDroid. That one works, and works well everywhere I have tried it.

I also see that this has not been updated since May 31, 2018. That is probably why it does not work. The developer has not kept up with the frequent video website changes.

Uninstalling.