namespace My\Extension\ViewHelper;
use My\Extension\Utility\LocalizationUtility;
class TranslateViewHelper extends \TYPO3\CMS\Fluid\ViewHelpers\TranslateViewHelper
{
    protected static function translate($id, $extensionName, $arguments)
    {
        return LocalizationUtility::translate($id, $extensionName, $arguments);
    }
}

<?php
namespace My\Extension\Utility;
class LocalizationUtility extends \TYPO3\CMS\Extbase\Utility\LocalizationUtility
{
    /**
     * @var string
     */
    protected static $overrideLanguageKey = '';
 
    /**
     * Returns the localized label of the LOCAL_LANG key, $key.
     *
     * @param string $key The key from the LOCAL_LANG array for which to return the value.
     * @param string $extensionName The name of the extension
     * @param array $arguments the arguments of the extension, being passed over to vsprintf
     * @return string|NULL The value from LOCAL_LANG or NULL if no translation was found.
     */
    public static function translate($key, $extensionName, $arguments = null)
    {
        if (GeneralUtility::isFirstPartOfStr($key, 'lang[')) {
            preg_match('#^lang\[(.*?)\]\:(.*?)$#', $key, $matches);
            // set key
            $key = $matches[2];
            self::$overrideLanguageKey = $matches[1];
        }
        [...]
            self::initializeLocalization($extensionName);
            /* NEW */
            $languageKey = self::$languageKey;
            if(self::$overrideLanguageKey) {
                self::initializeLocalizationFor($extensionName, self::$overrideLanguageKey);
                $languageKey = self::$overrideLanguageKey;
            }
            // The "from" charset of csConv() is only set for strings from TypoScript via _LOCAL_LANG
            if (!empty(self::$LOCAL_LANG[$extensionName][$languageKey][$key][0]['target'])
                || isset(self::$LOCAL_LANG_UNSET[$extensionName][$languageKey][$key])
            ) {
                // Local language translation for key exists
                $value = self::$LOCAL_LANG[$extensionName][$languageKey][$key][0]['target'];
            } elseif (!empty(self::$alternativeLanguageKeys)) {
            [...]
    }
 
    /**
     * @param string $extensionName
     * @param string $languageKey
     * @return void
     */
    protected static function initializeLocalizationFor($extensionName, $languageKey)
    {
        $locallangPathAndFilename = 'EXT:' . GeneralUtility::camelCaseToLowerCaseUnderscored($extensionName) . '/' . self::$locallangPath . 'locallang.xlf';
        $renderCharset = TYPO3_MODE === 'FE' ? self::getTypoScriptFrontendController()->renderCharset : self::getLanguageService()->charSet;
 
        /** @var $languageFactory LocalizationFactory */
        $languageFactory = GeneralUtility::makeInstance(LocalizationFactory::class);
 
        self::$LOCAL_LANG[$extensionName] = $languageFactory->getParsedData($locallangPathAndFilename, $languageKey, $renderCharset);
    }
}

$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['linkhandler']['generateLink'][] = \My\Extension\Hooks\LinkhandlerParameterProcessor::class;

<?php
namespace My\Extension\Hooks;
 
use Cobweb\Linkhandler\ProcessLinkParametersInterface;
 
class LinkhandlerParameterProcessor implements ProcessLinkParametersInterface
{
 
    /**
     * @param \Cobweb\Linkhandler\TypolinkHandler $linkHandler Back-reference to the calling object
     * @return void
     */
    public function process($linkHandler) {
        $configurationKey = $linkHandler->getConfigurationKey();
        if($configurationKey == 'tx_extension_myrecord.') {
            $record = $linkHandler->getRecord();
            $additionalParams = '&tx_extension_test[parent]='.$record['parent'];
            $additionalParams.= '&tx_extension_test[record]='.$record['uid'];
            $additionalParams.= '&tx_extension_test[controller]=Test';
            $typolinkConf = $linkHandler->getTypolinkConfiguration();
            $typolinkConf['additionalParams'] = $additionalParams;
            $typolinkConf['title'] = $record['title'];
            $linkHandler->setTypolinkConfiguration($typolinkConf);
        }
    }
 
}

$GLOBALS['TCA']['fe_users']['columns']['country']['config'] = [
    'type' => 'select',
    'renderType' => 'selectSingle',
    'itemsProcFunc' => 'My\Extension\UserFunc\TcaProcFunc->staticInfoTablesItems',
    'maxitems' => 1
];

<?php
namespace My\Extension\UserFunc;
 
use TYPO3\CMS\Extbase\Reflection\ObjectAccess;
 
class TcaProcFunc
{
 
    /**
     * @param array $config
     * @return array
     */
    public function staticInfoTablesItems($config)
    {
        $key = 'isoCodeA3';
        $value = 'shortNameLocal';
        $sortbyField = 'isoCodeA3';
        $sorting = 'asc';
 
        $objectManager = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\CMS\Extbase\Object\ObjectManager');
        $countryRepository = $objectManager->get('SJBR\StaticInfoTables\Domain\Repository\CountryRepository');
 
        $countries = $countryRepository->findAllOrderedBy($sortbyField, $sorting);
        $countryList = [];
        $countryList[] = ["", ""];
        foreach ($countries as $country) {
            /** @var $country \SJBR\StaticInfoTables\Domain\Model\Country */
            $countryList[] = [ObjectAccess::getProperty($country, $value), ObjectAccess::getProperty($country, $key)];
        }
        $config['items'] = $countryList;
        return $config;
    }
 
}

if (TYPO3_MODE === 'BE') {
    // Page module hook - show flexform settings in page module
    $extensionName = \TYPO3\CMS\Core\Utility\GeneralUtility::underscoredToUpperCamelCase($_EXTKEY);
    $pluginSignature = strtolower($extensionName) . '_pi';
    $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['cms/layout/class.tx_cms_layout.php']['list_type_Info'][$pluginSignature][$_EXTKEY] =
        'My\Extension\Hook\CmsLayout->getExtensionSummary';
}

namespace My\Extension\Hook;
class CmsLayout
{
    public function getExtensionSummary(array $params) {
        $result = null;
        if (strpos($params['row']['list_type'], 'myextension_') !== FALSE) {
            $pluginName = str_replace('myextension_', '', $params['row']['list_type']);
            if ($params['row']['pi_flexform'] != '') {
                $this->flexformData = \TYPO3\CMS\Core\Utility\GeneralUtility::xml2array($params['row']['pi_flexform']);
            }
            $methodName = 'bePreview' . ucfirst(GeneralUtility::underscoredToLowerCamelCase($pluginName));
            if (method_exists($this, $methodName)) {
                $result = $this->$methodName($params['row']);
            }
        }
        return $result;
    }
 
    protected function getFieldFromFlexform($key, $sheet = 'sDEF') {
        $flexform = $this->flexformData;
        if (isset($flexform['data'])) {
            $flexform = $flexform['data'];
            if (is_array($flexform) && is_array($flexform[$sheet]) && is_array($flexform[$sheet]['lDEF'])
                && is_array($flexform[$sheet]['lDEF'][$key]) && isset($flexform[$sheet]['lDEF'][$key]['vDEF'])
            ) {
                return $flexform[$sheet]['lDEF'][$key]['vDEF'];
            }
        }
 
        return NULL;
    }
 
    protected function bePreviewPi($row) {
        // whatever
        return '';
    }
}