I've looked through the MDN resources here as well as here, as well as the WhatWg Fetch Spec, and for all that I can't figure out if the Fetch API is part of ECMAScript 5, 6, 7 or otherwise.
All I can tell is that it isn't implemented consistently across browsers, and in some cases is not supported at all.
Yet the spec definitely defines Fetch as Javascript:
The Fetch Standard also defines the fetch() JavaScript API
Source: link
Is the Fetch API simply a proposal that is not on the books yet for ES 7/8, or is it actually part of ES6/7/8 and my Googling skills have failed me?