With PDF, it would not be hard to obscure the presence of only a minimum of legitimate content using many page-breaks to give the illusion of a long document, a

With PDF, it would not be hard to obscure the presence of only a minimum of legitimate content using many page-breaks to give the illusion of a long document, and filling those pages with space-hogs such as large headers, tables, and algorithmically generated graphics. The sparsity of genuine content would not be too surprising given that PDF was originally intended for printing rather than reading.