In case, one had written a book manuscript, but it was not possible to find, by other means, proofreaders mathematically knowledgeable enough to proofread the manuscript, would it be appropriate to ask on MathOverflow for volunteers doing the proofreading?
In the case at hand the manuscript (in German) is already accepted by a publisher, but the publisher says, they can not provide in depth proofreading because the book is too specialized/advanced and so the copy-editor will probably only check spelling, grammar and superficial consistency.