I found some background questions about this, but there doesn't seem to be a consensus.
What exactly are the "specific concerns" that are acceptable in the Proofreading closure? Phenry's answer, score of 7, says (regarding questions asking if a single sentence is grammatically correct):
If the questioner is clearly more interested in getting an answer than in understanding the answer (i.e., if it smells suspiciously like a "do my homework for me" question), I usually vote to close as Proofreading. If the question shows a good faith effort to understand what the problem might be, I usually let it slide.
Does this sort of question qualify as proofreading? Cerberus's answer, which has the highest score of 4, says
I feel that "proofreading" should normally apply only to longer texts, at the very least a paragraph.
The next-highest scoring answer (at 2) by Eldroß says
I would say that the question would need to be expanded to give some context. ... [If the assumption that there is something wrong with the sentence were] wrong, then it would be definitely off-topic.
- What the "proofreading" close reason is for MrHen's answer here, with a score of 2, says
The fundamental question around closing posts like these is whether answering the question will help anyone other than the person asking the question. [... questions of the form 'Is [example A] better than [example B]?' are not] inherently interesting and, by their nature, limit answers to content that is very unlikely to help anyone other than the asker. Therefore, I think most questions of this type should be closed. [...] it is better to close a bad question with a slightly incorrect close reason than it is to leave it open and encourage more bad questions like it.
Two recent events that made me think about this issue are the closing of the following question by MetaEd (https://english.stackexchange.com/questions/352905) as "proofreading" and the recent discussion in chat starting with this post by tchrist about the "proofreading" close reason.
How should this close reason be used? Does it matter? And if it does, should the description of the close reason ("Proofreading questions are off-topic unless a specific source of concern in the text is clearly identified") be edited?