wp-includes/Requests/src/Cookie/Jar.php:98Set the given item
$offsetstring$valuestring #[ReturnTypeWillChange] public function offsetSet($offset, $value) { if ($offset === null) { throw new Exception('Object is a dictionary, not a list', 'invalidset'); } $this->cookies[$offset] = $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/Jar.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.