How can one determine which additional packages are needed for specific PHP extensions?

To determine which additional packages are needed for specific PHP extensions, you can use the `phpinfo()` function to display detailed information about your PHP environment. Look for the "Loaded Configuration File" to find the php.ini file being used, and then search for the specific extension you need in that file. Once you identify the extension, you can install the necessary package using a package manager like apt or yum.

<?php
phpinfo();
?>