wp-includes/Requests/src/Cookie.php:370string public function format_for_header() { return sprintf('%s=%s', $this->name, $this->value); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/Requests/src/Cookie.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.