There was testing, but it was cut short due to a slightly earlier than expected release of Firefox 57 (Quantum), so I rushed it to get just alphabetical sorting out in 3.0. I didn't realize how many people relied on the "excluded folders" feature (I don't use it myself so it wasn't a problem for me). I'm working on an update, so check the GitHub site for the latest status. Also, don't forget to make backups of your bookmarks.