These are classes which extend the base
ColModifer class. They're used to decorate values prior to display, such as when they're rendered in an
Itemlist. For example, you could display the user's name instead of their numeric ID, or display 'Y' or 'N' boolean values instead of 1 and 0, or display dates in a format like "Mon 1-May-2017" instead of the actual database value "2017-05-01".
A subclass diagram showing all the ColModifiers and their relationships is available.