I got this on a question I asked (no big deal - I don't care if somebody closes it). Is this a feature? How would I access "private feedback"?
What that text is referring to (the "private feedback") is the explanation just above it.
Here's a snip from one of my own closed questions, with the feedback this text is referring to circled:
The text in this area changes depending upon who is viewing the page at a given time. The post author sees an explanation oriented just for them (hence the "private feedback for you" wording). Users with access to the close vote privilege see the reason the question was closed as well as who voted to close it, and users who are neither the post author nor a close voter will see a minimal explanation.
Here's what I see, as a user who does not have close vote privileges, on your closed question's post notice:
The private feedback is visible above that phrase, in this case something like this:
More details about these banners can be found in the announcement post: New Post Notices are live network-wide