TYPO3 Core

//TYPO3 6.2

//typo3/sysext/frontend/Classes/Controller/TypoScriptFrontend/Controller.php

public function previewInfo() {

if ($this->fePreview !== 0) {

$previewInfo = '';

if (isset($this->TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['hook_previewInfo']) && is_array($this->TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['hook_previewInfo'])) {

$_params = array('pObj' => &$this);

foreach ($this->TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['hook_previewInfo'] as $_funcRef) {

$previewInfo .= GeneralUtility::callUserFunction($_funcRef, $_params, $this);

}

}

$this->content = str_ireplace('</body>', $previewInfo . '</body>', $this->content);

}

}