So I was doing some trial/error in the in game world editor to prep. my prison prefab for Navesgane and something unexpected happened.
When the prefab would spawn into the world, a huge chunk would be missing. Upon loading up the prefab in the ingame editor and pilles editor, there definitely was a huge chunk missing. The bad news is I don't think I have a backup after I started adding sleeper blocks/volumes.
At worst, I need to redo sleepers from scratch again. At best, I can reuse the still existing prefab XML file which contains all of the sleeper volume properties. I would just need to re-add the sleeper blocks again......