I have just noticed at https://mathoverflow.net/review/suggested-edits/stats that a user user4148 who registered only today has already reviewed one suggested edit. -- How is this possible?
8$\begingroup$ I think it was an edit to his or her question. $\endgroup$– Yuichiro FujiwaraJun 19, 2014 at 22:02
3$\begingroup$ Yes @YuichiroFujiwara is right. OP decide on suggested edits too (irrespective of reputation); indeed approval of OP alone suffices. This happened in this case: mathoverflow.net/review/suggested-edits/23344 (Removed the tag 'bug' as it isn't one.) $\endgroup$– user9072Jun 19, 2014 at 22:14
2$\begingroup$ Sorry, I do not understand your remark. OP can indeed edit their post without anybody needing to approve it. But this would not create this entry. What happened is that sombody (Guillermo) suggested an edit and OP approved the suggested edit to their post (just like you and I [combined to be precise] could have done it). $\endgroup$– user9072Jun 19, 2014 at 22:53
$\begingroup$ @quid: Ah, o.k. -- that explains it. -- Thanks. $\endgroup$– Stefan Kohl ModJun 19, 2014 at 22:54
$\begingroup$ Glad this is settled. Independently of your comment I just searched for the "official reference" and will post it as answer for completeness. $\endgroup$– user9072Jun 19, 2014 at 22:56
While most of the time a suggested edit on a post is reviewed by users with the editing privilege, the author of a post can always review an edit suggested by somebody else on their post, too. Indeed, the vote of an OP is stronger than a normal vote, it alone can decide on the edit taking effect or being rejected (normally it takes two users).
For this and additional information see How do suggested edits work? (especially the section "Who can vote on a suggested edit?" in the answer).
Thus, it can happen that a new user reviews an edit. Yet, only if it is an edit proposed by somebody on their own post; this is what happened in the current case https://mathoverflow.net/review/suggested-edits/23344