This is a "special banner" featuring the player characters from the team Jackpot - aka the Splatoon 3 World Championship 2024 winning team. Once you've launched the game from the latest Splatoon 3 article, you'll be able to collect this banner from the in-game lobby terminal.
Last week, Splatoon 3 was updated to Version 8.0.0 adding a new season and catalog changes, changes to the game's multiplayer, Splatfest, Salmon Run, and various bug fixes across multiple modes in the game.
Will you be redeeming this free banner? Have you updated to 8.0.0 yet? Let us know in the comments.