This answer comes from deduction.
To figure it out ou have to figure out, on your own, how Apple decided to build the documents and understanding the programming lingo but mostly the logic behind the documents structure!
And even then it’s not explicitly written, it’s logical deduction and trial end error.
So In my case I wanted to know how -newObject got called. Remember that the target of the Add button is Cars -add:.
Cars inherits from NSArrayController.
NSArrayController has the method add:. There is not much in it’s documentation.
NSArrayController inherits from NSObjectController and it also has the method add:.
In it’s documentation it mentions “see -newObject”. This is the only location in the document that kind of links -add: to -newObject.
As a side note, the second you subclass -add:, -newObject no longer gets called.