The default 404 Response Provider budle with id org.apache.clerezza.platform.content.default404 provides an implementation of the PageNotFoundService (package/bundle: org.apache.clerezza.platform.content) that the delivers the response retrieved from the uri with the same protocol and host and the /page-not-found. For example if 404 is to be generated for http://example.org/foo/bar the entity obtained by dereferencing http://example.org/page-not-found will be returned.