IMO there's only two choices for storing Technology "owned" by the winners of the "War Against The Fallen". First would be under the Temple and second would be on TFNS Hamilcar (assuming that it still existed.
They built the Temple and it would be easier for them to create a hidden storehouse under the Temple that to build one elsewhere. Since we don't know if the TFNS Hamilcar still exists, we can't be sure one way or the other if they stored their high-tech stuff on it.
I doubt that Kau-yung and Shan-wei's faction stored high tech elsewhere than Nimue's cave. After all, why build another storehouse when you have Nimue's cave? Note, here I'm talking about high tech, it is still possible that Shan-wei created other storehouses of knowledge of the past similar to the one that exists in Tellesberg.
As for the pro-Langhorne losers in the "War Against The Fallen", I doubt that they were able to build anything similar to Nimue's cave. They won't have the time and couldn't do it secretly. Remember Kau-yung and Shan-wei created Nimue's Cave before the main fleet arrived at Safehold.
In addition, during the "War Against The Fallen" the factions that finally lost likely did not see the need to create secret storehouses. After all they didn't
know that they'd lose.
After they lost, assuming they weren't killed immediately, they'd be too busy hiding themselves to build a secret storehouse of any size. It's possible that gadgets belonging to them survived but anything the size of (or larger) their shuttles/aircraft was likely found by the winners centuries ago.
Now it's possible that some of the winners were able, after the War, to create small scale "hide-a-ways" but the question is why?
Considering what we're learning about Schueler, he might have created a "hide-a-way" but we just don't know for sure.
Rod wrote:O.K. I've thought about this for awhile. And really all I have are questions

First, I thought the hidden base was under Lake Pei. It would be easy to get to, it's right next door. But then I thought. What about Winter, how are you going to get out of the ICE? You could get out but every now and then, there'd be a hole in the ice. And that might be seen!
Then, I started running into problems thinking that the hidden base was under some mountain. Like the cave, how did they get from the temple to this tech base. Is there a road headed up some hill that has a sign. ARCHANGEL's only, Do not pass this point! NO? So how about a transport system under the temple to this base?
Or did they have a computer like Owl to remote the ships? If they did it like this the hidden base could be full of Nitrogen and alot of the storage problem would be fixed.