Including Directories in Locate on Mac OS X

Can anybody shed light on which directories OS X decides to put in the locate database and which it decides to omit? It's pretty clear that ~/Library is out - which others? And how do I modify this so that every time updatedb is called, it actually scans all my directories?

Yes, this question has (sort of) been asked before: http://ift.tt/1I7g32n

But it wasn't answered well, and the question of default directories for the (cron task?) updatedb never even came up.

Thanks so much!!