ConstReadonlyDefault: "default"One set for every page.
ReadonlyFirstAndDefault: "firstAndDefault"The first page's own, then one set for the rest.
ReadonlyFirstOddAndEven: "firstOddAndEven"The first page's own, then odd and even pages.
ReadonlyOddAndEven: "oddAndEven"One set for odd pages and one for even pages.
Which sets of headers and footers are used.