The GlobalFetch mixin of the Fetch API contains the GlobalFetch.fetch() method used to start the process of fetching a resource.

API Experimental Fetch GlobalFetch HTTP Interface Networking Reference request

The fetch() method of the GlobalFetch mixin starts the process of fetching a resource. This returns a promise that resolves to the Response object representing the response to your request.

API Experimental Fetch Fetch API GlobalFetch Method Reference request