What is the purpose of using TL_ROOT in PHP, and how does it relate to server configurations like open_basedir restrictions?

When dealing with server configurations like open_basedir restrictions, it is important to use TL_ROOT in PHP to specify the base directory of the TYPO3 installation. This helps ensure that file paths are correctly referenced within the TYPO3 environment and prevents issues related to open_basedir restrictions.

define('TL_ROOT', dirname(__FILE__) . '/');