Show the available video links.
当前为
Tags every video link on a YouTube page so that they can be downloaded easily, using the title as the filename. On the watch page, it also shows all the available video formats at the top of the page.

When a VEVO video is first accessed, the video links will not be shown because the de-obfuscated code is gotten too late. You need to manually refresh to see the links. This should happen just once — until YouTube changes the de-obfuscated code again.
If the video links are still not shown, it could be because the script does not recognize the new de-obfuscated code anymore. This happens once every few months; it is a cat-and-mouse game. Post in the forum so that I know about it. :-D
The video link does not show the video formats on hover in Firefox.
Taken directly from http://userscripts-mirror.org/scripts/show/110007.html