The extension allows you to download the kind of files that you play in the browser.
On the sites, the video can be built in by standard methods of Chrome as a file, or as a stream through site's own video player. In the second case, the extension will display a link to the streaming playlist, which can be downloaded by third-party software, such as the VLC video player.
Chrome extensions can not offer to download videos directly from YouTube, due to copyright protection. Please note that we do not promise such functionality.
If with some site does not work, please do not rate us bad, better write what to improve to the developer firstname.lastname@example.org
Good feedback motivates us to do better, we do not charge any fee for using the extension.