"Reply filtering" is a separate service that can be setup for your account that collects replies to your emails. Reply filtering is used to keep automated responses from being sent back to a real email address, like out-of-office replies. Additionally, reply filtering can be used to identify replies that should be unsubscribed.
Reply filtering comes with standard filters that will be used to identify and catch automated responses. You can also create your own filters once reply filtering is setup in your account.
Legitimate responses (in most cases) are delivered to the configured email address.
If you are interested in learning more, please reach out to our Client Success Team at firstname.lastname@example.org for information on our Standard Authentication service which includes Reply Filtering.