"...serving a dummy page." It could also be less than a page. It could be a dummy resource. For example, in the case of an ad server and a smartphone app tha

"...serving a dummy page." It could also be less than a page. It could be a dummy resource. For example, in the case of an ad server and a smartphone app that has some screen space reserved for ads. You might want your own resource to appear in that space instead. Another example is reverse engineering API's and protocols for popular web services, social media, storage, etc. In that case you might want a "dummy server" that serves certain responses.