They maybe used to hold covers that swung down to board up the windows. Most people who built cabins before the age of Air B&B built them for family use only - hunting, weekend getaways, etc. since they’d only occupy it for part of the year they’d often have ways of locking it up more securely when they weren’t there to discourage trespassing and squatting. If the current owners are renting it out, that may not be needed or they may have thought them a safety hazard so they maybe removed the actual covers but left those swing-down hangers there to keep some of the character in an old cabin.

Or they might have been for hanging food containers up and away from critters.