https://codegolf.codidact.com/posts/283917 is a feature request for a change to tags on Code Golf. But it arose out of a problem: indicating that a sandbox post has now been finalized and posted in the challenges category.

If we could close a post as a duplicate of a post in a different category in the same community, they wouldn't need to use tags or title labels to indicate this at all, and there would be a clear path from the sandbox post to the challenge.

Meta has occasionally had questions that are duplicates of proposals in Site Proposals. Outdoors could get questions (in Q&A) that are duplicates of questions in Gear Recommendations.

While it might sometimes be handy to close per-community meta questions as duplicates of questions on main Meta, this is not that request. I don't want to open the door to cross-community duplicates when communities have different standards and expectations, but within a community, can we allow this?