Any block of non-XML data, sometimes referred to as a binary entity because its content is often a binary file (such as an image) that is not directly interpreted by the XML parser. An unparsed entity could contain plain text, so the term binary is a bit misleading. Unlike a parsed entity, an unparsed entity requires a notation, which identifies the format or type of resource to which the entity is declared. Beyond a requirement that an XML parser make the identifiers for the entity and notation available to the application, XML places no constraints on the contents of unparsed entities.