Modern browsers are very complicated programs, especially because they also need to be secure to protect users from countless threats on the interwebs. That means that the plugins functionality is necessarily quite limited. Firefox used to have XUL extensions, allowing to have the powerful
vimperator; but from Firefox 57, only WebExtensions API is supported. There is a replacement for
vimperator written with the WebExtensions API:
tridactyl, however it’s more limited.
Lots of websites now provide video content. But sometimes videos have ads, sometimes the player’s interface is inconvenient, or the video is blocked on the page even though it can be loaded if you know the link.
youtube-dl is an amazing program that can download videos from dozens of websites. How do you make it work with your current tab in Firefox?