wp-includes/Requests/src/Cookie/Jar.php:70Check if the given item exists
$offsetstringboolean #[ReturnTypeWillChange] public function offsetExists($offset) { return isset($this->cookies[$offset]); }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.