With some articles, rvparse and rvsection don’t seem to work together, e.g. http://en.wikipedia.org/w/api.php?action=query&prop=revisions&titles=Iron%20Maiden&rvprop=content&rvsection=0&rvparse&format=yamlfm. All page content is returned. Without rvparse it works but that’s not what is desired. Workaround is action=parse, but that could be too limited.