Want to know more? No, because then you will threaten to sue us. The legal action is frivolous and will lose in the end but it will cost money time and attention to deal with.
But forget all that, seriously now, what's the real reason, the applicant asks? For us, if we didn't make an offer it's either because the applicant is a jerk, a liar, or incompetent. One or more of these covers the situation with the majority of applicants. Salary is not an issue, we pay what it takes for the right people. I can't say the same for other companies, they often want to find someone cheap. Jerks don't change, the incompetent can't improve, and liars only use feedback to make their lies harder to detect. This means all feedback is either useless or counterproductive. There is one exception. The rare case they are a sweet genius with severe BO. In this case little can be gained from feedback since there's little chance one is not aware of it. If one suspects BO might be the reason, then it is and it should be fixed before the interview.