These commands make up one of three obsolete menu schemes that, somehow, continue to work in Visual FoxPro. A truly hot item back in FoxBase, these commands let you create a popup menu using an array to contain the commands. If you do things just right, you can probably combine these menus with the light-bar menus of @ ... PROMPT and get something that looks almost like a Windows-style menu. Why bother?
@ ... MENU and READ MENU have no place in Visual FoxPro applications. Use the Menu Designer and standard Windows menus.