It sets up configuration used by the requirejs (r.js) task. You're right that it sort of looks like a no-op though. Anyhow, the config is printed to the terminal:

```
  requirejs:
  { dist: 
   { options: 
      { baseUrl: 'src',
        optimize: 'uglify2',
        generateSourceMaps: true,
        useSourceUrl: true,
        preserveLicenseComments: false,
        useStrict: true,
        wrap: false,
        exclude: [ 'text!config.json' ],
        uglify2: {},
        name: 'main',
        out: 'dist/main.js',
        mainConfigFile: 'src/main.js' } } }
```