Running a Next.js application gives the default message in the console

ready - started server on 0.0.0.0:3000, url: http://localhost:3000

When I use Postman to make a request to an API endpoint on the request URL http://0.0.0.0:3000/api/{a-valid-end-point}, I get the correct response. When I try to run the same request from the browser console of the application, CORS blocks it.

const res = await fetch("http://0.0.0.0:3000/api/{a-valid-end-point}");

// Output Message
// Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource
// at http://0.0.0.0:3000/api/hello. (Reason: CORS request did not succeed). Status code: (null).

From my understanding, browsers implement CORS. Tools like Postman do not have this feature.

What is the IP address 0.0.0.0:3000 actually doing here?