Periodic replacement. Cyclically replaced, or eliminated due to poor sales. Generally, McDonald's will update their menu periodically, so there will be some single items that will be replaced, or eliminated early due to poor sales, but there will be another similar product to replace it. For example, the Asparagus Burger is not available, but the existing Multi-Bamboo Shoots Roll is very close to the Asparagus Burger in terms of ingredients, which is also asparagus, onion, and chicken, so you can choose this one if you like the flavor of asparagus.