It would be nice if the IResourceCachingStrategies provided Wicket export the extracted version for the lifecycle of the request.
An application may need this version to be able to check later whether the requested resource is the one that the system will actually deliver.
E.g. web container 1 may deliver the page markup to the browser and then disappear due to upgrade. Then all requests for the resources in that page will be automatically redirected to web container 2 that may have new versions of the resources. In this case the application may return 302/303 (redirect) or 404 (Not found) or whatever is the best for the case.