<?php defined('TYPO3_MODE') or die(); \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::makeCategorizable( 'dd_events', 'tx_events_domain_model_event', 'categories', [ 'label' => 'Categories', 'fieldConfiguration' => [ 'minitems' => 0, 'maxitems' => 3, 'multiple' => true, ] ] );