Many modern vehicles have engine trim which is usually for aesthetic purposes only, but sometimes protects the engine in some minor way. It is usually plastic material with the engine's size or appealing qualities written on it, like Variable Valve Timing, displacement, manufacturer, or even an engine model name.
Usually this trim is meant to hide the engine, due to a naturally unappealing or complex appearance. In a small number of cases, the trim is actually used to channel air around the engine for cooling purposes. Sometimes, the trim has functional parts integrated into it, such as air intake tubing.