<p>Anyone can review, and approve or deny, edits to their own posts.  That is the case whether the post at issue is a question or an answer.  Moreover, their review is final:  That is, if they are the first reviewer, there is no need for a second, and if they are the second reviewer, but their review disagrees with the first, their choice is used.  </p>

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<p>When your reputation is >10k(?), you can see more of what's going on in the review queues.  It appears that was <a href="https://stats.stackexchange.com/users/140470/user125535">user125535</a>.  They approved an edit to their own post.  Here are some screenshots:  </p>

<p><a href="https://i.stack.imgur.com/b4N24.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/b4N24.png" alt="enter image description here"></a></p>

<p><a href="https://i.stack.imgur.com/EEvGR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EEvGR.png" alt="enter image description here"></a></p>

<p>Note that it is unlikely they went straight to the review queue and found this suggested edit.  They would have been notified through their inbox and followed a link to the suggested edit to approve or reject.  </p>
