Why does a React functional component function with no hooks run twice on creation (or mounting)?

Question

I created this minimal React snippet and when reloading it, I get:

I'm not even using props, state or any other hooks, why would React need to call it twice?

    function Component() {
      console.log("running Component()", Math.random());
      return <>Hello</>;
    }

    export default function App() {
      return (
        <div className="App">
          <Component />
        </div>
      );
    }

CodeSandbox