http://6pb473duz5o6kdvedrvplpyce33ezwjxkehbwtagytxe6yqal4xe44yd.onion/articles/xmpp.html
There isn't much emphasis given as to what those backups will contain. Is it the information they previously outlined under "What Data is Stored", alongside account information e.g username, password, avatar, etc, and nothing more? Or is there metadata contained as well?