Pretty straightforward ask here.

CHANGED_COLOR can detect when the Tint or Alpha of any face of an object has changed.

CHANGED_TEXTURE can detect when the Texture of any face has changed.

CHANGED_LIGHT could detect when variables for PRIM_POINT_LIGHT (on/off, tint, intensity, radius, or falloff) have been changed by hand or by script, and when the variables for the projection light (texture, FOV, focus, or ambience) have been changed.