Configure Buttons
From Starfy Wiki
Configure Buttons (Japanese: キーコンフィグ, Key Configure) is an option in The Legendary Starfy that is accessible via the Pause Menu. Although it has no icon, it can be accessed via the L button.
It allows the player to adjust the controls for abilities. By default, the Y button is used for dashing/the Star Spin and the B button is used for jumping/the Turbo Swim. The player can adjust the controls so that the Y button is used for a Star Spin, the B button is used for dashing/the Turbo Swim and the A button is used for jumping.