Does exactly what it says it does. No more autoplaying previews. Nice and clean look, 10/10 extension

Firefox needs restarting for it to work.
I was looking for a way to permanently disable previews and this worked.
The "video previews" switch in youtube's settings needs to be disabled per-device and also turns itself back on after a while(!).
And this add-on seems to disable previews permanently. Thank you!