Right now there is no real content except to explain. The data-icon helps you to put an icon on the toolbar and then the href will send you based on the address. You can bring up the data-icons with a search - one location is jquerymobile.com/test/docs/buttons/buttons-icons.html
After I found the CSS problem when I was writing the navigation bar examples, I went back and added rel="external" here as well. See notes under my navigation bar examples.