Recently deleted posts can be accessed by a link at the bottom of the Answers and Questions tabs in your profile. The question above was deleted more than 2 yrs ago, so even if it was in your current account, it wouldn't be accessible by normal means (there a SEDE script that will show links to them). With a direct link to it, you should be able to access it, though. If your old account is undeleted, it can be merged with your current account. Merging needs to be done by SE staff (superuser.com/help/merging-accounts), and they can also undelete the account.

If it was a self-answer, the OP could still see it and retract or change the acceptance. If it was someone else's answer and the OP lacked the rep to view deleted posts (10K), I'm not sure whether they could see it on their own thread. In that case, unaccepting it would probably require moderator intervention to temporarily undelete it.

Excellent question about deleted answers. Acceptance is at the discretion of the OP, and I don't think it's directly tied to deletion status (although a deleted answer can't be accepted if it's not already). I think I remember seeing deleted threads (the question gets deleted, taking the answers with it), and a deleted answer still showed the acceptance. If I'm remembering correctly, then deletion of an accepted answer would leave the acceptance in place, and there can be only one accepted answer. (cont'd)

@DánielKis-Nagy, thanks. This is surprising because the script reads the info from the timeline data. I would have thought that if you can see the timeline, and see the review results directly, there wouldn't be anything in the script requiring higher permissions. It looks like for some reason the user needs review privileges for the script to see the review results. Appreciate your checking.

@Mokubai, might that be one of the reasons 125 rep is required to downvote? Yeah, interpreting those votes needs to consider the context.

@CaldeiraG, LOL. I linked to the original script created in 2012, which defaults the site to SO. The ones you found and edited are exact copies created today by an anonymous user, that defaults to SU. It looks like you went to the queries list instead of the direct link, sorted it by Recent, and those were at the top. Maybe somebody who saw this post went and played with the script and saved it. And now there are two new copies of those copies you edited for attribution. :-)

Also, we're not sure what rep is required to view the timeline on a question. This is a link for yours: superuser.com/posts/1456112/timeline. Are you able to view that? Thanks for your help.

Dániel, can you help us test something? You weren't aware of the reopen review on your question. We've created a user script to allow people to see that, but we don't know what minimum privilege level is needed for it to work. We know that some level is required because it doesn't work if you aren't logged in. Your rep is still relatively low on SU. Could you load the script and see if it works for you? It's described here: Announcement: New Functionality. (cont'd)