Since we have proper starting points for User hub, Sysadmin hub, and Developer hub, why are we maintaining pointless incomplete lists in Manual:Contents as well?
I propose this point to those three sections and that's it.
Topic on Manual talk:Contents
As I understand, initially this page was understood as the "table of contents" for some virtual book called "technical manual for the MediaWiki software". This should have been the main entry point to the "Manual:" namespace (in these same role as Help:Contents for "Help:" namespace).
If currently this page is completly substituted by Sysadmin hub and Developer hub, then this page may be deleted.
My understanding is that User hub is the entry point to the Help NS, and that the Sysadmin and Dev hubs are entry points to this technical manual (i.e. all pages in the Manual NS).
I think the Manual:Contents should be a complete index to all (top-level) pages in the Manual NS. There seem to be about 600 at the moment (excluding hooks, variables, and filenames). I know the Category:Manual is meant to be that, but it's easier to navigate on a single page.