It looked promising.
As it turns out, it's a plugin for a (scientific?) host called praat. But once installed hosts a vast array of offline vocal tweak and copy operations some of which I have never seen before but have been after. Like pitch envelope copy from a guide track to the singers track who didn't do it like you did for example. All kinds of copy operations and cool tweaks like converting a vocal track to a whisper.
Just super.
Windows and Mac by the way.
http://www.praatvocaltoolkit.com/index.html