When Roomba deletes a question, does it always end up in the "deleted recent questions" list? If not, in which cases will the question not end up in the "deleted recent questions" list?
The previously accepted answer is no longer correct.
The answer to this question is now an unequivocal "yes", because the page now lists all questions deleted within the last 60 days, even if they were posted earlier.
This change was announced in February 2020, but that answer was deleted as it had been posted on the wrong question. Unfortunately, no non-deleted official announcement of the feature change exists.
It is entirely dependent on how long ago the question was posted.
The "deleted recent [posttype]" lists is reserved for posts which have been posted in the previous 60 days and are currently deleted.
If the Roomba cleans up a question posted within the last 60 days, it will appear in the owner's "deleted recent questions" list. Additionally, any answers to Roomba-ed questions which have themselves been posted in the previous 60 days appear in their owners' "deleted recent answers" list.
Questions (and answers) older than 60 days do not appear in these lists, regardless of how recently — and how — they were deleted.