I Want To Set My Default Admin Username Or Password

The admin identity is Magium\Magento\Identities\Admin and extends Magium\Magento\Identities\AbstractEntity. The abstract class extends AbstractConfigurableElement which means that you can use configuration to change the defaults.

<?php

$this->username = 'newadminuser';
$this->password = 'NewPassword';

Project file: /configuration/Magium/Magento/Identities/Admin.php