TYPO3 Core

Line 481 ff:

            if ($pp[0] != $pp[1]) {
                $481resultData['titleaddition'] = ', ' . LocalizationUtility::translate('result.page', 'IndexedSearch') . ' ' . $dat['key'];
            } else {
                $resultData['titleaddition'] = ', ' . LocalizationUtility::translate('result.pages', 'IndexedSearch') . ' ' . $pp[0];
            }

As the first condition is the one with several pages ranges is has to be result.pages in line 481 and result page in line 483.