To find this cache, a little cryptanalysis will be required. The
following message can be decoded in a very straightforward (if
atypical) manner. It may be very simple for you, or it might be
very difficult. Hints will be added over time for as long as it
remains unsolved, but for now, no nudges will be given. Good
luck!
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