You are tasked with backlog refinement.

The product backlog has become cluttered with old and unclear issues. You need to groom the backlog:

1. Go to the backlog.
2. Find two issues that got the same name or describe the same problem.
3. Open one of these issues.
4. Select "Close issue"
5. Choose "Duplicate issue" as closing reason.
6. Save/close issue.

Focus on making the backlog a reliable source of upcoming work.