Secret Government Warehouse-The Ministry of Ghosts maintains one of these, called the Silent Library. Where it is and how it works is kept a very, very strict secret [1], but for the very few that know about it, it does the job of keeping things stored very, very well. To the best of anybody’s knowledge, there hasn’t been an accidental release of anything from the Silent Library since it was built. Considering some of the things that are stored there (one of which is a zombie plague), that’s saying a lot.
The Griffin Moot’s Special Working Group maintains the Ghost Floats-under the theory that a moving target is better than a stationary one, no matter how secret or well protected. It’s known that the minotaurs and zebras maintain their own depositories, but what these depositories are and how they work are so secret that they might not even know what they do or how they work. All they know is that things are kept secure and that’s all they need to know.
What happens when changelings get ahold of dangerous artifacts…usually requires somebody else to deal with the problem. Often by a saturation bombardment from orbit.
[1]-The Silent Library is basically a Earth-sized huge ball of metal orbiting a pulsar in an orbit that sweeps it through the radiation bands every 10 hours. Dug very deeply into the planet is the Silent Library, which incorporates all sorts of additional security systems, from AI-driven guns to massive physical separation of dangerous artifacts from anything that might come in contact with it. Oh, and several very large anti-matter weapons to make sure nothing ever gets out.
Getting to the archive is tricky. You have to come out of Tunnel Drive from one of only three or four stars that gives you a trajectory that doesn’t slam you into the radiation bands. Then, you have to get your ship into dock on the planet before the planet itself goes through a radiation band (this limits you to ships of less than 100,000 tons, since anything larger can’t use anti-gravity). And, you have to get through the automated defenses that will shoot first, shoot again, and interrogate the remains if you don’t identify yourself properly.