Um, you think you might want to retract those statements? W3C and WHATWG aren't the Internet Police. They may recommend you follow their conventions when writing code but they're not going to give you a ticket and shut down your website because you didn't strictly follow their code. Modified HTTP code only means my browser won't work correctly with your website (your loss not mine) and improperly coded HTML4 just means I can't see your site as you would want it to display. Again, not my loss. Only someone with no clue would code improper HTML or HTTP code.Also, supporting modified or unofficial HTML4 & HTTP client & server software is FROWNED UPON, not only to both the W3C & WHATWG, but also to book publishers that published books related to the older HTML versions in the Mid-1990s to Late-2000s.
And, I have all the mentioned manuals in my library.
Forgot to add, Adobe issued an update for Flash Player that actually uninstalls it from your system. How's that for a timebomb?
(my unofficial HTML5 contribution)