Earlier quoted context omitted.
Is there an article with the background on this? Why do we have both the W3C and the WHATWG, and why do the W3C just copy and paste work from WHATWG, if that is indeed what happens?
The W3C was the original standardization organization for the web. They wanted to create standards that allow easy implementation by others, and were willing to make some tradeoffs with backwards compatibility for that (see XHTML). The browser vendors obviously oppose this, and want standards that just formalize what they already implement. As result, the browser vendors created their own standards committee, which s…
The HTML5 spec effort that gave birth to WHATWG wasn't simply about documenting backwards compatible parsing, it was about vendors like Mozilla and Opera wanting to evolve HTML in a way that added actually useful new features, something that W3C had zero interest in at the time.
Nowadays, the W3C's behaviour seems to be driven entirely by an institutional desire to justify its own existence, and protect its revenue stream and its self-assumed position as the one-true source of web standards, by engaging in bad-faith practices like taking standards produced through the hard work of others, removing all citations, making breaking changes, and publishing it as a competing "standard".