Confirming the Identity of a (Friendly) Reviewer After the Reviews Somewhat a follow-up to this post.

I recently had a paper reviewed, and in receiving one of the reviews, I feel strongly that I know the identity of one of the reviewers (someone with whom I'm on generally friendly terms, but not enough to be a COI). Unfortunately, the paper didn't quite make it in, so we're looking to make the requisite changes and resubmit elsewhere.

Out of sheer curiosity, I'd like to reach out to this individual to ask if they were a reviewer for this paper. However, I believe this may be inappropriate, and have thus avoided doing so. Is it ever appropriate to ask such a question, and if so, when? I suspect doing so before the paper is accepted elsewhere is likely a faux pas for many reasons, including selfish ones (e.g., getting this reviewer again after making the suggested changes would likely be quite beneficial).

While not strictly relevant to the question, it's worth noting that this reviewer gave an extremely helpful and thorough review, though they ultimately gave a weak reject. In my reaching out to this reviewer, it would be solely to ask whether or not they reviewed the paper, and not discuss the review whatsoever (regardless of how they responded).
No, this is why the review process is anonymous...

Any "reaching out", while you say it is only to find out if they did or did not review your paper (and others will think "well that's because they want an inside track"...) will put the reviewer in a difficult position whether you intend that or not.

The reviewer's reputation with the journals they work with is important to them, so while you might be curious, don't go there.