The k prefix to a variable implies it’s a constant. It’s usually followed by programmers who use the Hungarian notation, which I need to read a little more about.
Core data actually can store in XML (Human readable, works well if you want to share your data with apps other people write, for obvious reasons), binary data format and SQL Lite. I was under the impression that it was only SQL Lite for some reason.
Core data can also enforce relationships among objects (m:n)