Yeah, I ended up giving youtube-dl + the GUI for it a shot (external app, of course), it works just fine and offers me the simple interface I want. I'll miss how easy it was to do things with add-ons and extensions with Firefox pre-v57. I use the YouTube Video and Audio Downloader (Dev Edt.) with my FirefoxESR Portable v52.9 and I know that's the end of the line for it but that add-on just made it so much easier - just two clicks in the browser and poof, done. The good old days... long gone I suppose.
Those who have been using the "tab hover cards" will notice a small improvement in the animation when switching from one tab to another after today's update in Edge Canary, now that animation is better and smoother, the difference is subtle but noticeable.
The latest Google Chrome Canary build now comes with a new settings page similar to Microsoft Edge Chromium.
I was able to reproduce the "blink or flicker bug" of the "tab hover cards" with the flag set in Enabled, if the flag is set to Enable B or Enabled C, the bug doesn't happen (at least in mi case), for those who don't remember, these options control the time it takes for the card to appear after hover the pointer over the tab, I have always preferred option B, I don't like that the card appears immediately.