it work!!!

Work-around for missing download button (thanks Rosa)
...(display YouTube video page)
Tools > Browser Tools > Web Developer Tools (or ctrl-shift-I)
Inspector (tab)> Search HTML (field)> #eytd_list (press enter)
...(displays 1 of 2)
(press enter)
...(displays 2 of 2. box at right: element display: none)
highlight "none" > change to "block"
...(displays popup upper left with download options)
select an option
...(displays "Save As" dialog)

Very useful extension!

GOOD

This app is easy to use and effective.

It worked fine when I first used this addon. But after some days, the download as button is not showing up. So I rated 4 stars.