SevenCubed - 3:35 am on Oct 11, 2012 (gmt 0)
Thanks very much for taking the time to track all this down phranque. That's going to be lots of reading to catch up on. What I do realize after skimming this is we haven't been on the same page in the sense that I've been approaching this as someone who uses XHTML 1.1 served as HTML and still using the current checker. It appears what you are presenting here is related to HTML5 and referring to the i18n-checker. But I did try it out anyway on my current sites and it does pass saying "no issues to report". I'll continue to use XHTML 1.1 served as HTML because of it's tighter validation rules (unless someone can convince me otherwise). I've determined that sticking to that DTD helps my sites be presented equally as well on mobile devices as desktops thereby eliminating the need for a separate mobile site. I'll stay with it until HTML5 becomes more supported by browsers, probably another 2 years (or 4 years in MSIE time).
And I actually took a closer look at my source and in fact I do have a bunch of stuffing in the opening <html...> That's what happens when we develop a boilerplate, we tend to forget or ignore what we stuffed into it originally...
This is the meat and potatoes of what I use:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xml:lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd" >
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<meta name="language" content="en-CA" />
Lots of standards to catch up on!