ES6 vs esversion:6

I’m pretty new still so I apologize if this is a very basic question, but what is the difference between ES6 and esversion:6?
I’m just starting the algorithm challenges and I passed the Find the Longest Word in a String challenge, but it threw out a warning and I don’t want to move on until I understand why.

The line of code with the warning:

var max = Math.max(…newArray);

The warning:

‘spread/rest operator’ is only available in ES6 (use 'esversion:6).

Did I solve the problem the wrong way?

If you google esversion, you’ll find that it’s a configuration option in jshint, a javascript linter. You’re using the ... syntax that only came in ES6. I’m guessing FreeCodeCamp uses jshint to check the code and that’s why it raises a warning. I wouldn’t worry about it.

Thank you I appreciate it. It didn’t make sense when I tried to google it.