Does not work at all.

Just offered options for HDQ and LQ, but no setting works.

i have low bandwidth in parts of my home.
so the "i-auto-your-video-quality-because-reasons-youre-welcome-greetings-youtube" is very annoying.
this extension works like a charm.

neg:
can't select a higher quality manually in the video options (e.g. if i want to read something that's shown in a video). the extension will force it back.

tip:
don't activate/change the quality of the extension if you have >50 youtube tabs open.
it will reload them all at once.

edit:
doesn't work anymore. not recommended

Useless.