The 'Hello Dolly' plugin is a classic “Hello World” application that utilizes a simple code to display a random lyric from the song in the upper right corner of the WordPress dashboard. This plugin is meant to have no real purpose or to aid with any specific functions, and is mainly used as a way to demonstrate certain coding techniques. It was also created to serve as a friendly reminder to users that WordPress is still evolving, and that people are continuously creating more plugins and other personalized features.

The code behind the 'Hello Dolly' plugin is relatively basic. It consists of one PHP file which saves the lyrics for the song, a “readme.txt” file which provides instructions to users interested in downloading the plugin, and an “admin.css” file for styling purposes. When a user activates the plugin, it then sends the lyric to the “admin_notices” WordPress action hook, which allows the plugin to display the teaser in the dashboard of any WordPress site. The lyrics are then displayed on the WordPress dashboard from time to time while users are logged in and working in their sites.

Aside from displaying a lyric from the Louis Armstrong song, the 'Hello Dolly' plugin can be used as a base for learning how to code. It provides an easy platform for developers to learn how to create basic WordPress plugins. New users can also use the plugin as a way to delve into the WordPress file structure and see how different coding techniques work.