cakephp/tests/test_app/config/var_test2.php

<?php
return [
    'Read' => 'value2',
    'Deep' => [
        'Second' => [
            'SecondDeepest' => 'buried2'
        ]
    ],
    'TestAcl' => [
        'classname' => 'Overwrite',
        'custom' => 'one'
    ]
];