Deletes the canvas information from a canvas (construction) plane.
All the paint information (brush strokes, masks, background color, opacity, etc) is removed from the canvas plane, but the plane itself remains in the scene and can be used as a regular construction plane. (See Create or edit a reference plane and Work with the construction plane.)
To delete the canvas plane as well as the paint, pick it, then either press the key, or choose Delete > Delete Active.