.settings.php

См. документацию.

<?
return [
    'controllers' => [
        'value' => [
            'namespaces' => [
                '\\Bitrix\\UI\\Avatar\\Controller' => 'avatar'
            ],
            'defaultNamespace' => '\\Bitrix\\UI\\Controller'
        ],
        'readonly' => true,
    ],
    'ui.uploader' => [
        'value' => [
            'allowUseControllers' => true,
        ],
        'readonly' => true,
    ],
];