Well, the question is why does it need to be a secret?
1) is it for plot reasons? This seems most likely. Revealing it would give too much away.
2) Is it because it's a bit of homebrew that they are not sure people will like? I think this is not likely, Larian would want to get feedback on homebrew. I mean at least they know we don't really like BA shove.
I can't think of any other reasons to not reveal something but I am putting money on its a plot detail thing that ties into the Dead Three and has to do with some sort of interaction we have with them.
