And can be found on dKosopedia.
It is not an official document maintained by site administration , but almost all of it is sourced to official statements by site administration, so it probably as close to official as you're going to get. If you need more than that, kos described this as "helpful" in comments to my last diary and suggested information to include, so I feel safe in saying that it's not completely worthless and that you probably won't go wrong if you adhere to it.
It is a wiki, so anyone can contribute. Although I've put some work into compiling information, I don't own this document. Feel free to sign up for a dKosopedia account if you haven't already and introduce yourself in the discussion page for the article.
I began this project because of the Great Purge of 2011. As people voiced their concerns about HR abuse, I started to look into what was considered HR abuse. There was a FAQ that addressed some of this, but it was de-linked from the frontpage because it was obsolete. It needed to be redone, but no one seemed tasked with doing it.
I was about to unleash this, when the boycott came. The participants included people whose questions I had hoped to address, so I waited until it was over. I hope that this document provides clearer understanding for those who boycotted and for those whose behavior contributed to people feeling there was a need for a boycott. I make no comment here about past behavior (if it comes up in the comments, I might), but I hope that going forward there is a better understanding of what is permissible.
It's not a big, fat rulebook, but it's more than "don't be a dick". I think there is enough there to extrapolate how most behavior will be judged without having to spell everything out. You should, for example, be able to understand that "don't be a dick" combined with inconsistent usage of ratings being considered abuse means that shouldn't be a legalistic dick, citing and interpreting guidelines to favor your side with a narrowness that Antonin Scalia would be proud of.
I've described this as a potential sub-FAQ for a larger Daily Kos FAQ. From my perspective, such a FAQ needs to be broken down into parts. At a minimum, I think separate FAQs for technical issues and meta issues (such as site policies) are necessary just to make things manageable. I have my eye on a few areas where I might write additional FAQs, but I'm not writing an entire site FAQ by myself (unless someone pays me to do it). Rather than a skeleton of an entire FAQ, I think it works best if people or groups dedicate themselves to writing a sub-FAQ. I hope I have provided a useful model, where one party takes the initiative of creating a first draft that others can comment upon. When enough parts are completed, the difference pieces can be assembled into a larger FAQ tree. I am interested in working on such an effort.
I hope this also illustrates the use of dKosopedia to organize information. It's there, so we might as well use it. For example, groups on Daily Kos can create a group FAQ to include information that doesn't fit on the group profile page. For highly-trafficked groups that deal with contentious issues, this can include addressing often-stated points of contention. It might be helpful if there is a boilerplate answer that people can quote and link to instead of continually re-hashing old debates. Ideally, that provides a bridge toward the gathering and organization of non-meta information.
Bonus meta: Here's a list of DK groups with a geographical basis.