edit: please keep your promise
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hi, you 1. click the 'Improve Youtube!' (extension icon, top right of browser),
2. 'Player' 3. 'Rotate' (you will find a new button in the youtube player)
-2. Alternatively you can just Type 'Rot to enable the feature
( please understand we are hardworking volunteers and blackmailing with one star rating is not right. There should be big reason. It can frustrate us for a long time. Even with 4 stars the pressure is real.)
many smiles