Web(Cache)Browser is an application that allows to browse Safari's cache content. So it is possible to retrieve resources that have been downloaded by the web browser, for example to use them offline.
You can find specific elements thanks to the search field or by selecting a type of resources to display.
Web(Cache)Browser also allows to individually delete some elements from Safari's cache in order to save disk space. In this case, it will be efficient to use the sort-by-size feature to display the biggest resources on the top of the list.