Somtimes below a question body this text block is placed:
We're looking for long answers that provide some explanation and context. Don't just give a one-line answer: please explain why you're recommending it as a solution. Answers that don't explain anything will be deleted. See Good Subjective, Bad Subjective for more information.
I think I understand what types of questions "attract" this banner: questions that are conducive to guessing or giving undocumented short answers that are hard to verify.
My question is: when and how is this banner added to a question? Can we help moderators by flagging questions that may need this text?