What addon could this be?

[Wimpface]

I came across this screenshot, from BatiUI, and I got stunned by seeing skinned achievement popups!

I'm very interested in finding the addon that does this, I looked through the addon list (I even downloaded the UI and checked for textures, nothing.) but I couldn't find any addon that does this.

Here's the screenshot in which you can clearly see the achievement popups being skinned.



Thanks in advance,
Wimpface.