TYPO3 / TYPO3.CMS

        // Looking up the page record to verify its existence:

        $page = $tsfe->sys_page->getPage($linkDetails['pageuid'], $disableGroupAccessCheck);

        if (empty($page)) {

            throw new UnableToLinkException('Page id "' . $linkDetails['typoLinkParameter'] . '" was not found, so "' . $linkText . '" was not linked.', 1490987336, null, $linkText);

        }

        foreach ($GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['typolinkProcessing']['typolinkModifyParameterForPageLinks'] ?? [] as $classData) {

            $hookObject = GeneralUtility::makeInstance($classData);

        $mount_info = $tsfe->sys_page->getMountPointInfo($page['uid'], $page);

        if (is_array($mount_info) && $mount_info['overlay']) {

            $page = $tsfe->sys_page->getPage($mount_info['mount_pid'], $disableGroupAccessCheck);

            if (empty($page)) {

                throw new UnableToLinkException('Mount point "' . $mount_info['mount_pid'] . '" was not available, so "' . $linkText . '" was not linked.', 1490987337, null, $linkText);

            }

            $MPvarAcc['re-map'] = $mount_info['MPvar'];

        }

        // Setting title if blank value to link