Magento2.4.6 - Why X-Magento-Cache-Debug is not displaying in the response header?

Question

I want to use cache GraphQl query for a custom module.

I have created an Identity class and added @cache in the schema.graphqls.

And Model file extends \Magento\Framework\Model\AbstractModel and implements \Magento\Framework\DataObject\IdentityInterface.

My Question: Why X-Magento-Cache-Debug is not displaying in the response header?

I'm using Built-in-cache and Postman.

Thank you.