Terrible Junk - SCAM-WARE Rated 1 out of 5 stars
Total garbage - deserves 0 stars but there is no such option.
DO NOT GET THIS PLUGIN
It is a scam - it installs other rubbish without your consent - it does not work properly, and it attempts to make you download some other garbage video player.
THIS ADD ON IS SCAM-WARE
It DOES have some basic function but even that is not very good, the sole purpose of this junk is to promote its authors and their other garbage software - To Mozilla : this plugin should be banned.
There are FAR BETTER video down-loaders out there that actually WORK and don't scam advertise you anything - for example - "VideoDownloadHelper"