Hi, I am interested in working on this issue. Can you please elaborate on the problem statement. What exactly do you expect. Do you want a front-end visualization of differences between 2 consecutive revisions of XML/JSON file or you want a backend functionality for the same.
Another thing would be that we could store the inserted, updated and deleted nodes (only the node keys ordered numerically and based on a delta encoding and the type of operation (insert/update/delete)) in an index-structure, such that comparing consecutive revisions is super cheap.
But I think a serialization format now would be more important in the first place.