Basically, data for Siren to be used in battle. It's unclear if this is a one time event battle for the Torna DLC, or whether it can be used for all of the Torna DLC, and whether it can be used in the main game. It seems to have something to do with Blade Combos and Party Gauges, so it may or may not function such that it replaces Chain Attacks or Full Burst for the Torna DLC. There's also data for an enemy Siren (most likely the Malos version), etc. There is no indication that it can be used in the overworld outside of combat (like exploring while flying with it).