What are some practical uses of Lua in Mac OS X?

I see many text editors for Mac OS X that support Lua syn开发者_如何转开发tax highlighting, but I have yet to see an example of Lua being used in action in the actual Operating System.

How is Lua being used practically?

World of Warcraft addons use Lua, among many other games. Some games use it as a "private" scripting language that isn't available to users.

Here are some other uses of Lua.

I believe Cortex Command (an awesome indie game) uses it as a scripting language, for one.