wp-includes/Requests/src/IdnaEncoder.php:143Check whether a given text string contains only ASCII characters
$textstringbool protected static function is_ascii($text) { return (preg_match('/(?:[^\x00-\x7F])/', $text) !== 1); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/Requests/src/IdnaEncoder.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.