title: How come, Webpack directly imports webpack.config.babel.js?
body: <p>I am new on a pretty big ReactJS project. On top level, it does <em>not</em> have  the usual <code>webpack.config.js</code>, but only a `webpack.config.babel.js'. That this one does indeed get used I can verify, when running</p>
  
  <pre><code>&gt; webpack
  </code></pre>
  
  <p>gets called (through <code>npm run</code> with NODE_ENV=development and WEBPACK_CONFIG=server_dev², but that should not matter much).</p>
  
  <h3>Why is that so?</h3>
  
  <p>a) If I remove that babel-config, I get a rightful complaint, that:</p>
  
  <blockquote>
    <p>A configuration file could be named 'webpack.config.js' in the current
    directory.</p>
  </blockquote>
  
  <p>b) If, instead, I add my own do-almost-nothing <code>webpack.config.js</code> that one indeed “rules” (with <code>webpack.config.babel.js</code> no longer being used).</p>
  
  <hr>
  
  <p>So, apparently, there's an “invible” default <code>webpack.config.js</code> that kicks in, if this file is missing. And again, apparently?, this default configuration somehow caters to the webpack-configuration? By what? By virtue of having those node-modules installed?</p>
  
  <p>Or is <code>.babelrc</code> a marker file of sorts to webpack?</p>
  
  <p>Interestingly, this project, <a href="https://github.com/developit/preact-www" rel="nofollow noreferrer"><code>preact-www</code></a> project has the same thing. (nor original webpack config, but the webpack flavour). So they know something, I don't...</p>