To reiterate on point 1: A damper is a device used to regulate air flow from the fireplace to the chimney. It is most often located just above or on top of the fireplace, inside the chimney. From outside it can generally be operated via a metal handle.

If you have an open fireplace it is unlikely that it doesn't have one. Without it it would be impossible to prevent air from travelling through the chimney even if the fireplace is not used, which causes heat loss.
If your fireplace is enclosed, it might be possible that air flow is regulated by some other means, for example a vent underneath the fireplace.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence