NSExtensionServiceTouchBarBezelColorName
The color to use for the bezel around the extension when it appears as a Quick Action in the Touch Bar.
Discussion
This key is used in conjunction with the NSExtensionServiceAllowsTouchBarItem key.
Set the NSExtensionServiceTouchBarBezelColorName key’s value to the name of a color that exists in your extension’s asset catalog—a color that matches a system color is recommended. If no color is specified, a default color is used.