WHATWG stands for Web Hypertext Application Technology Working Group.
The group was formed as a response to the slow development of the W3C (World Wide Web Consortium) web standards in 2004 by indviduals of Apple, the Mozilla Foundation and Opera Software.
The aim of WHATWG is to evolve the web, especially HTML, by creating and extending standards and tests.
Since 2019, WHATWG is the sole publisher of the HTML and DOM standards, while their approaches on HTML standards were the "de-facto" standard for years already.
Information on how to participate within the WHATWG can be found on Participation - WHATWG (opens in a new tab).
Read more about the WHATWG on their official FAQ Page (opens in a new tab), their Wikipedia Page (opens in a new tab), their HTML Standard FAQ Page (opens in a new tab) or their own Wiki (opens in a new tab).
The FrontendNetwork Docs are not directly associated with the WHATWG, even though the members of FrontendNetwork are also participants of the WHATWG.
The main goal of the FrontendNetwork Docs is to provide documentation for the WHATWG Wiki, especially for the MetaExtensions page which you can learn more about here.