The 
Fetch Standard defines requests, responses, and the process that binds them: fetching
Standardizes the browser networking library
Sits between APIs (<img>, fetch()) and HTTP
Abstracts requests and responses to handle other URL schemes and browser specifics (e.g., CORS)
Integrates content security policies, referrer policies, HSTS, redirects, port blocking, service workers, …
Exposes (some) control over redirects, client-side HTTP cache, credentials, …
