The component element describes the component of the product that this topic is concerned with. For example, a product might be made up of many components, each of which is installable separately. Components might also be shared by several products so that the same component is available for installation with many products. An implementation might use this identification to check cross-component dependencies when some components are installed, but not others. An implementation might use the identification to make sure that topics are hidden, removed, or flagged in some way when the component they describe isn't installed.