The Curvature contour shader traces a line whose thickness depends on the angle between normals of adjacent faces.
So if two normals are in nearly opposite directions, there is a contour of width close to Max Width between them. As the angle between them decreases, the width of the contour decreases almost to Min Width.
The color used for rendering the contour lines.
The minimum contour width, in percent of the image size.
The maximum contour width, in percent of the image size.