The "Abocado Aerospace & Defence - US Letter FrameMaker Template" (yeah, it's a long name) is an Adobe FrameMaker template. It has been custom built to work within the area of aviation, aerospace and defence documentation. These industries have some very specific requirements for their documentation needs.
The main objective is one of documentation granularity. It is important to keep track of all pages, all revisions and have unique id's for all items. In order to track all this stuff, the template must be able to generate, what is called a "List of Effective Pages".