Note well: The maximum length of the result string for Slider.Format is limited to 32 characters. If you need more, you must use Slider.Stringify.
Slider.Format defaults to "%ld".
The string you specify here can use text formatting codes. See Text formatting codes for details.
mui.Set(obj, "Format", "Custom text: %ld")The code above sets the slider text to "Custom text" followed by the current slider level.