THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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When it sees a response with a "Location: ..." header and a "Digest: SHA-256=..." header, it checks to see if the URL in the Location header is already cached. If it isn't, then it tries to find a URL that is already cached to use instead. It looks in the cache for some object that matches the digest in the Digest header and if it finds something, then it rewites the Location header with the URL from that object.
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