specifically, message from Ray Smith dated 7/15/13
"Cube is a perfect example. It doesn't do much useful, yet now everybody wants it documented, so there is no way I can commit another half-baked experiment that isn't production-ready that everybody will want documented. I have 3 new classifiers in addition to cube that haven't delivered on their early promise. It really is hard to beat the current classifier, although I am starting to understand why a little better.
The good news is that I really really want to get the Google version of the code cleaned up and synced with the outside world this quarter, as there are some improvements in there worth having.
"
specifically, message from Ray Smith dated Oct 30, 2014
regarding plans for 3.04 release