The majority of eReaders accept EPUB files due to this and the fact that it is a freely accessible standard. EPUB files are called layout agnostic, which means that the screen’s size has no bearing on the formatting-they can view content on screens as small as 3.5 inches. Words, images, stylesheets, fonts, metadata information, and table of contents can all be stored in EPUB files. How to Read EPUB Files on Windows or Mac?.What kind of content can be stored in EPUB files?.