Learner is hitting the nail on the head. The connotation is not negative as Englishlearner1 implies; rather it means something good is being protected and kept safe until a future event when the time is right to present the masterpiece. Everybody knows about it, it's no secret, but nobody can see it until the time comes. Learner also gave some good verbs to express the event. Good Q.

Learner's right - when we wrap something up, we are hiding what it is (think of a Christmas present).

'Under wraps' is an informal expression meaning 'being kept secret or concealed until some future time'. Therefore, 'unveil' and 'reveal' are antonyms for 'keep under wraps'.

I think there is something unethical covered and the contract dose't mention to it. and after singing the contract the unethical action or that covered plan become protected legally. May be .....