This cache is a challenge cache:
It is at the posted coordinates, even though it is an "unknown" cache type.
You are not allowed to log a "find" without proof that you qualify by completing the caching related "challenge" below, but you can make a write note.
Challenge:
To log this cache, you must have filled the 81 matrix grit (all D/T combinations) with at least one cache.
You can attach a proof to your log (optional).
Logs that don't fulfil this condition or contain a fake screenshot will be deleted without any comment.
As the owner of this Challenge Cache I have to fulfil the cache condition myself.
https://project-gc.com/Challenges/GCA5VC3/75886