YouTube™ Dual Caption 3.6.6 Update Instructions
In the 3.6.3 version, the video quality lock function is provided, but when automatic is selected, the picture quality is still locked and cannot be adjusted dynamically. This problem is now fixed.
Preset subtitle styles were provided in previous versions, and the subtitle default style is now consistent with YouTube.
If you need to revert to the default style, you can click the Reset Style button.
Right click on the extension icon and there are upgrade instructions and a YouTube channel.