Not understanding filesowner

I’ve been through half of the big nerd ranch ios book and still don’t quite understand the purpose of the files owner. Currently, I’m following this tutorial: appcoda.com/customize-table- … tableview/

This tutorial doesn’t set a filesowner, but everything still works… ??? What is going on? For those of you who don’t want to read the tutorial, this is the gist of it:

It creates a custom UITableView cell through a xib file. This xib has a UITableCell with 4 objects in it(1 image 3 labels). The image and 2 labels are IBOutlets. The UITableView Cell has a custom class set in the identity inspector however. Is this custom class then the file’s owner? If so, what’s the point in the explicit “files owner” placeholder near the top of the UI(next to first responder)?