A check for language name differences between MediaWiki core and CLDR (via https://www.mediawiki.org/wiki/Extension:CLDR)

CheckLangNames.php

<?php

define('MW_PATH', '../../');

require(MW_PATH . 'languages/data/Names.php');

$coreLanguageNames = MediaWiki\Languages\Data\Names::$names;

echo "{|\n";
echo "! Lang !! In core !! In CLDR\n";

$dir = opendir('CldrNames');
if (!$dir) {
	echo 'Unable to read CldrNames';
	return;
}

while (false !== ($entry = readdir($dir))) {
	if (preg_match('/^CldrNames([^.]+)\.php$/', $entry, $matches)) {
		$lang = strtolower(str_replace('_', '-', $matches[1]));

		// unset($languageNames);
		require( "CldrNames/$entry" );
		$hasCore = isset($coreLanguageNames[$lang]);
		$hasCldr = isset($languageNames[$lang]);
		if (!$hasCore || !$hasCldr) {
			echo "|- lang='$lang'\n";
			echo "| $lang || ";
			echo $hasCore ? $coreLanguageNames[$lang] : "''undefined''";
			echo " || ";
			echo $hasCldr ? $languageNames[$lang] : "''undefined''";
			echo "\n";
		} else if ( $languageNames[$lang] != $coreLanguageNames[$lang] ) {
			echo "|- lang='$lang'\n";
			echo "| $lang || ${coreLanguageNames[$lang]} || ${languageNames[$lang]}\n";
		}
	}
}

closedir($dir);

echo "|}\n";