Official Version versus Latest Version

I just noticed that the current/latest of Understanding and Techniques documents are now labelled as being the quote Official Version unquote.

  *   When did this change start happening?  (It might well have be a while back, and I am just noticing now!)  Is this a trend with other W3C docs?
  *   Was the change discussion on a AGWG call?  (And if so, what was the date please, as I would like to re-review the meeting notes.)
  *   Is the term “Official Version” defined anywhere?  (If so, link please.)



Thank you.