Updating cache directory
Each entry in this section lists two URIs—the first is the resource, the second is the fallback.Both URIs must be relative and from the same origin as the manifest file.All requests to such resources bypass the cache, even if the user is offline.
In Firefox, the offline cache data is stored separately from the Firefox profile—next to the regular disk cache: Offline Web Content and User Data See also clearing the DOM Storage data. If an application's manifest file is removed from the server, the browser removes all application caches that use that manifest, and sends an "obsoleted" event to the attribute in a web application can specify either the relative path of a cache manifest file or an absolute URL.
There are several reasons why you would want to purge the Windows Update cache.
Doing so will allow you to instantly reclaim valuable storage space by deleting obsolete update installation files.
Click the Save as type drop-down menu, and select All Files. In doing so, you will automatically delete the content of Update cache folder.
This document, titled "How To Purge the Windows Update Cache," is available under the Creative Commons license.