ext_localconf.php
<?php
defined('TYPO3_MODE') || die('Access denied.');
call_user_func(
function ($extKey) {
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['typo3/backend.php']['constructPostProcess'][] =
\ChristianEssl\Tabmoduleclick\Hooks\BackendControllerHook::class . '->addJavaScript';
},
$_EXTKEY
);