I wrote code to do this in python for a project. The biggest problem I ran into was that if you wanted the full history of X/Y/Z.json to contain the full history of Z.json, even if it had been moved, it ended up requiring two parallel structures. One structure with directories for the tree data, one for the raw data of that node.

My intent was to use it in a document system using Operational Transforms, which side-stepped the issue of concurrent access; only the canonical representation of client data would need to be written, so it was serial writing