That's pretty strange. If they're using it in a meaningful way, then they're applying it to arbitrary files, so they'd generally need fixes for almost all the bugs. So what resources would be lacking so badly that they give up on releasing?
It could just be a lame excuse. Open sourcing with zero support would be better than not doing it. But I imagine that this seems valuable enough to keep secret, or at least not to pay money to polish up for external use.
