You can adapt an OpenUI5 app to your specific requirements. For example, you can adapt or replace views, extend or replace controllers, or change language-specific texts.
The extension of OpenUI5 apps uses the component configuration. The extension information is stored in a specific area of the component configuration. It can be performed on a custom app that extends a delivered standard app. A replacement or extension of views and custom controllers can also be part of a custom app, but may not always be required. If no replacement and no custom controller exists, the custom app project only contains the component definition with the extension configuration. The standard app itself is not changed. The customized app becomes the start-up project and launches the standard app with the additional extension configuration.
For more information, see Using Component Configuration.