<?php
//Corp.Extname:Container2col5050.html
list($extie, $file) = explode(':', $dataHandler->checkValue_currentRecord['tx_fed_fcefile'], 2);
list($prefix, $extName) = explode('.', $extie);
$extKey = GeneralUtility::camelCaseToLowerCaseUnderscored($extName);
$label = $GLOBALS['LANG']->sL(
    'LLL:EXT:'
    . $extKey . \FluidTYPO3\Flux\Form::DEFAULT_LANGUAGEFILE
    . ':' . 'flux.' . substr(strtolower($file), 0, -5)
);
$fieldArray['header'] = $label;