I would like to clarify something that I don't think is clear in the post on automatic post deletion rules.
The first automatic delete rule kicks in at 9 days for closed questions:
If the question was closed more than 9 days ago, and ...
- was not closed as a duplicate
- has a score of 0 or less
- has no answers with a score > 0
- some other criteria that don't matter right now...
Then, at 30 days, there's:
If the question is more than 30 days old, and ...
- has −1 or lower score
- has no answers
- is not locked
This rule applies to both open and closed questions, but it doesn't mention the same exemption for duplicates.
I'm pretty sure that I've seen old, downvoted duplicates disappear on ServerFault (and that fits what the rule says), but I'm also sure I've seen lots of comments along the lines of "duplicates aren't deleted."
So what I'm after is a clear statement from a power-that-be or a clear reference that says "duplicate questions fall under the same 30-day automatic deletion rule as any other question." (or that they don't)
(Note: I realize this doesn't apply the stub left behind when a question is merged into another. Those "stubs" are locked and are never deleted.)