(3 secs) One of the libraries I work on is scaffolding_extensions, which is a very flexible admin frontend for multiple web frameworks and ORMs.
One of the things it allows you to do is override pretty much all of the defaults.
For example, you can set the default fields to be displayed on the pages for the Person model to be name and age, but to also show the position field on the browse page.
I'm going to go over two of the internal methods that implement this support.