The Data Entry URL box contains an Uniform Resource Locator (URL), which is used by an application to acquire more information about the associated vendor-specific extensions. The URL type should be the kind that delivers a file (for example, files, http, ftp, etc.). Ideally it permits random access. Relative URLs are permissible and are relative to the file containing this Data Entry URL box. This box is defined in JP2 and above file formats.
For an example, refer to Jpeg2000Engine.FragmentJpxFile example.