(Guest post by Allister Banks) Working with modern tools in the ‘auto'(dmg/pkg) suite, it sure reinforces the old chestnut, ‘it’s turtles XML all the way down.’ The thing that struck me when first diving into using autopkg was that different product recipes could potentially have a good amount of similarities when they share common processors. One example is drag-drop apps that can be discovered with an ‘appcast’ URL, which, in my recollection, became common as the Sparkle framework gained popularity. This commonality is exactly the type of thing sysadmins like myself seek to automate, so I built a few helper scripts to 1. discover what apps have appcast URLs, 2. generate the base…