It is actually a campfire, not a fire pit like at AKL and Kidani Village.
Here is the info from the POR/POFQ website/official thread.
Enjoy stories and family sing-a-longs while making your own smores around an evening campfire. There are two campfire locations, Riversides Campfire on de Bayou is behind the Muddy Rivers pool bar on Ol Man Island, just next to the childrens playground while French Quarters Cajun Campfire overlooks the Sassagoula River from the courtyard just behind building 6. The events are free, and optional smores kits (including Graham crackers, marshmallows, chocolate and sticks) are available for purchase for $7. The campfires are lit around dusk at 7:30pm during the summer months and as early as 5:30pm in the winter months, please see the Recreation Activities Schedule page for current times.
You can find additional info regarding POFQ activities on the portorleans.org website or the office POFQ thread.