This variable is used on character-based hosts to specify the color and video attributes of characters displayed in a message box window. MESSAGE_BOX_COLOR can be set to a variety of numeric values that express combinations of color and video attributes. See the documentation for the COLOR phrase in the "Common Screen Options" section of the Reference Manual (section 6.4.9 ).
If MESSAGE_BOX_COLOR is set to "0" (the default value), the message box is displayed with the default window colors and attributes.