title: Is there a standardized ES6 file extension? If so, what is it?
body: <p>I'm wondering if there's a standardized file extension for ES6 yet. So far I've seen <code>.es6</code> and <code>.es6.js</code> as two options, but I'm curious if one is generally better supported by third party packages and tools. And if Mozilla is leaning a particular direction.</p>