Also: the API gives very specific info about the game only — it does not give you anything and everything about the game. How APIs work: companies create interfaces to allow others to access their data publicly. The companies themselves (Supercell in this case) own the database and resources about their data, but they don’t provide everything about their database.
It‘s a bit like: if someone wants to know your schedule, you can publish your Google calendar for them, with some permissions like seeing when you are busy but not showing all the event details. You can also potentially have multiple calendars where you will share with your family and not your friends. APIs work a bit like that, in that you select what you want people to see. Having an API does not mean that you can know everything you can about the company / the game, or in this example, your full schedule with all the details.