This question is an exact duplicate of: Page Not Found

Question

I stumbled upon this question which was marked as a duplicate, and rightly so as the OP had realised himself in their comment.

Checking out the question that it's an exact duplicate of leads to this.

I get that people with sufficient rep can see this with no problem, but for others like me (and those that aren't part of the math.se community), this seems like a bit of a dead end. What should be done in cases like this?

Some thoughts that I've had are:

• Undeleting the page not found question may be against the wishes of the person that deleted it in the first place, but for a question to have been marked as a dupe with respect to the page not found question it must have had some answers (right?)
• Someone with sufficient rep could just copy over an answer that's deemed good enough and unmark the question as a duplicate.

A similar meta post is this, but this question falls outside of the January 2015 period referenced to in an answer to the question. Furthermore, there doesn't seem to be an answer for what should be done about dead ends like this.

Answer 1

Usually, duplicate targets are not deleted. They cannot be deleted by votes. Only, auto-deletion can happen, yet usually duplicate targets are not eligible for auto-deletion as they need to be answered to be valid dupe-targets.

Yet, there is an exception, when the two posts are from the same poster, which was the case here.

This is a known corner-case and by design. See What happens to duplicate targets that are eligible for auto-deletion?

Answer 2

• Undeleting the page not found question may be against the wishes of the person that deleted it in the first place, but for a question to have been marked as a dupe with respect to the page not found question it must have had some answers (right?)

Ordinary users (even moderators) cannot delete duplicate targets since early last year. Before a duplicate target can be deleted by users, the posts closed as duplicates of it need to be reopened [they may be reclosed for other reasons or as duplicates of a different question] or themselves be deleted.

Occasionally, however, an automated process deletes duplicate targets as dead/abandoned questions (that's probably a bug, not very high priority because what gets deleted that way is usually not very valuable, but getting a 404 after following a duplicate link is not good user experience).

When you come across such a situation, please raise a flag (not for this instance of course), so we can deal with it in the appropriate way.