Control the YouTube Music tab in the browser with your keyboard.
The extension controls your browser via AppleScript by running JavaScript in the YouTube Music tab. You must enable Allow JavaScript from Apple Events in the browser you select in the extension preferences; otherwise commands will fail (often with "Unknown Error").


After enabling this setting, pick the same browser (or WebCatalog app) in the extension’s Browser where YouTube Music opened preference.
Credit to @alexstrnik for the Yandex Music extension which this extension was based on.