ext_tables.php

<?php
if (!defined('TYPO3_MODE')) {
    die ('Access denied.');
}

// Register Page TSconfig for inclusion
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::registerPageTSConfigFile(
        'linkhandler',
        'Configuration/TSconfig/Page/news.ts',
        'EXT:linkhandler - Configuration for "news"'
);
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::registerPageTSConfigFile(
        'linkhandler',
        'Configuration/TSconfig/Page/tt_news.ts',
        'EXT:linkhandler - Configuration for "tt_news"'
);

// Register static TypoScript templates
if (\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::isLoaded('tt_news')) {
    \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addStaticFile(
            'linkhandler',
            'Configuration/TypoScript/tt_news',
            'Link handler - tt_news'
    );
}
if (\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::isLoaded('news')) {
    \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addStaticFile(
            'linkhandler',
            'Configuration/TypoScript/news',
            'Link handler - news'
    );
}

// Add tx_linkhandler type to linkvalidator
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPageTSConfig(
        'mod.linkvalidator.linktypes := addToList(tx_linkhandler)'
);