At the bottom of the file is this:

    ########################################################################################################
    #                                                                                                      #
    #                                                                                                      #
    #      Public Functions for Building XML = to replace/incorporate the function of XMLWriter.php        #
    #                                                                                                      #
    #                                                                                                      #
    ########################################################################################################

.. which is where I am trying to incorporate the functionality of the XMLWriter class back into this EprintsWrapper class.
In this file, in lines 428 - 453 I am trying to get rid of XMLWriter, as I am trying to incorporate this functionality back into EprintsWrapper.php (See bottom of EPrintsWrapper.php)
At the bottom of index.php, there are some tests.  Here, I established that:

the hash is the MD5 hash of the UNENCODED file contents
the filesize is the length of the UNENCODED file contents