what is listing?
definition
Listing is writing a list of things.
example
The door opened on to a tube-shaped hall like a tunnel: a very comfortable tunnel without smoke, with panelled walls, and floors tiled and carpeted, provided with polished chairs, and lots and lots of pegs for hats and coats - the hobbit was fond of visitors. (from the opening of The Hobbit by JRR Tolkein)
explanation
A writer uses listing to add emphasis to a point, show they are knowledgeable or to offer a variety of ideas in the hope that the reader will be familiar with one or several of them. In this example, Tolkein has added a list to create a vivid image in the reader's mind. The items in the list also give us information about the hobbit's character.