General Merchandise
in 5. Armory, Resources and PurchasingWorld Codex
The majority of this material is derived from the Dark Heresy Rules.
It is a repository of stats notes.
For game mechanics other than the home rule versions, descriptions and the full color and panoply of this amazing universe, please refer to the various core rule books.
For a different take on the rules used try the Wrath and Glory ruleset.