These scripts offer you a starting point or simple template that allow you to get Oauth2 setup on your own server or VM. A possible use case for setting up Oauth2 is if you are looking into configuring or building your own API.
To starting using the scripts, update the database connection details in the server.php script and include the oauth2-server-php library (https://github.com/bshaffer/oauth2-server-php).