If you're interested, the Visio team a basic help topic out for working with the file format of the new Visio 2013
http://msdn.microsoft.com/en-us/library/office/jj228622(v=office.15) (http://msdn.microsoft.com/en-us/library/office/jj228622(v=office.15))
David Parker just added a great posting on his blog about Visio 2013 file formats
http://blog.bvisual.net/2012/07/25/visio-2013-file-formats/
Finally, I've uploaded the pkgVisio to codeplex. The url is http://pkgVisio.codeplex.com/documentation for working with the file formats as well.
The two intro videos are over here
http://www.youtube.com/watch?v=7LvDKJuP9oQ&feature=youtu.be
http://www.youtube.com/watch?v=ZIWSXhNSkG8&feature=youtu.be
hth,
al
Duly noted:
New File Formats for Visio 2013 (http://www.visguy.com/2012/07/27/new-file-formats-for-visio-2013/)
Thanks, Al!