Hi Brenden,
I've discussed this with our security team and it seems that the mentioned XML file is still located in the application folder because of historical reasons but it's also required in some specific scenarios, e.g. when you are running a web farm where is the cross-domain communication used. I've deleted this file from my instance and everything seems to be working fine, it's related to the multifile uploader but also after the file deletion, uploader works without any problem, so create a backup of this file and feel free to delete it.
Regards, Martin