I'm wondering where the height of a cache is stored. I've always thought that that information is available with geocaching.com, but just not published on the cache page. But then the other day someone told me that geocaching.com doesn't have this data and the fact that we can look it up in Project-GC is only due to the fact that the latter is comparing the coordinates against surface height data.
The reason why I ask is for caches like this one: http://coord.info/GC5X63A . According to the owner, the cache is set at a height of -31,5 meters, but under the surface. I've suggested with the CO to check with geocaching.com if they can set the cache height accordingly. But I may have sent them to the wrong organisation?