wp-includes/rss.php:702$scfunction is_redirect ($sc) { return $sc >= 300 && $sc < 400;}Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rss.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.