Amiibo download files, also known as amiibo data, are small digital files that contain information about the character, such as its name, appearance, and abilities. These files are stored on the Nintendo console, whether it's a Wii U or a Nintendo Switch, and are used to recognize and interact with the amiibo figure. When an amiibo is brought near the console, the download file is triggered, allowing the character to be recognized and integrated into the game.