What do you understand about a CQ5 overlay/override component?
When you wish to work with an out-of-the-box component (Each out-of-the-box component is a set of scripts that completely perform a particular task in order to achieve the desired functionality) in AEM as well as wish to incorporate more functionality to it and change it overall instances of that component, you use the overlay/override component. If you want to incorporate functionality to the out-of-the-box "text" component but don't want to develop a new one, you can copy the "text" component to "apps/foundation/components" from "libs/foundation/components" while maintaining the same folder structure. Any modifications made to this new component will be mirrored in the out-of-the-box "text" component, without requiring any changes to the existing code under "libs". Modifying the original code is often not a smart idea, therefore, CQ allows you to utilise overlays.
