to make it work again on firefox just download and install their app and manually update the extension idmmzcc3.xpi restart the firefox, download video button will appear again on youtube, well at least for me

Its really nice to have IDM and it's really easy for me download item in fast time. thanks idm.

One can download any Videos, GIFs on Internet (With the main software installed). Most amazing & best Add-On / extension. This extension is definitely "SAFE".

inn

good