This definitely seems to be abandoned. I've had a bunch of issues with the tool in newer versions of Unity and there's some issues that have been flagged a year ago and haven't been fixed. The source code is also all locked away in a .dll (which is understandable) but it means that you can't even fix any issues yourself.
I loved this tool but can't recommend it in its current state. It's just going to get harder and harder to use as Unity continues to be updated.