Wow Interface Addon Kit Updates

[Elderin]

How often is the WoW Interface Addon Kit updated? Or, perhaps, more specifically, how long does it take to see new information in the Addon Kit?

For example, when I look in my interface\addons folder I am seeing Blizzard_PetBattleUI, however a fresh download of the Addon Kit does not include that "addon". I recently had an ingame discussion with a GM and he informed me that those Blizzard_* folders were not really addons but are templates for addon developers to use. As such I sort of expected to see the equivalents in the Addon Kit.

What I am really looking for are the frames, code, etc that implement the fading "You Won!" message. It is also used to notify the player of additional informtion, such as additional loot that the player is receiving.

Perhaps someone already knows the answer. But, I really expected to see that code in the Addon Kit.