A methods section is very common in areas such as medicine. However, in math
or computer science papers I rarely find such a section if no experiments or
observational studies were conducted. Nevertheless, it is a requirement for
the computer science journal I submitted to. While nearly none of the papers
published by the journal provides one, I still have to fulfill this requirement.
While some general guidelines can be found, for example in this question,
it would be very helpful to have some good examples for such a section in existing math or computer science literature.
Edit: As clarification: I already submitted and got a revision request that did not mention a missing methods second. I then submitted a revision and after a few hours I got a second revision request asking for a methods section (and a few other formal requests). I know that I could discuss this with the editor if I really need one, but maybe it would actually improve the paper.