This is a top-level (no-parent) page that serves as the parent page for important pages that will not be accessed through the sidebar menu that appears on the front page. Most of them will be accessed through the header menu.
There are a handful of other top-level pages that are accessed from the footer Developer Menu, including the Blog archive page (that shows all posts), as well as the pages currently filed under Site Developer Notes and Destined for Trash. (This last is parent to well over half of the pages on this site, imported from 5CLIR.)