The amount of pressure this post will generate is enough to generate a twitter update post from Alex in <24 hours.
On a serious side, from what I know, Codex hasn't been touched in ages since there's supposed to be a complete rework (retouch?) of it some day. So that's probably why it isn't implemented yet. Don't mistake my response as a way to give an excuse, I've been asking about the Codex touch up for ages, the answer usually being "when I get to it". Which is fair, game should first have the story and end game content, then fluff and extra features.