What Does Arguments_ Refer To?

I am trying to implement some plugins and found references to arguments_ but, it is coming up as undefined in the console. I cannot find any references online to this variable but

Solution 1:

Looks like js2coffee translates arguments to arguments_ -- that's a bug. Should be arguments.

Solution 2:

Every function has an array-esque arguments object available in it's scope. It contains information such as what called the function, what arguments they passed, etc.

What you see with arguments_ is most likely a third-party library that has stored some arguments variable from a specific function to be used later by their other functions. Without knowing what libraries you are including, though, it is impossible to tell.