src

The src-folder of the package should contain all the package specific source code. This means any Controller, RequestHandler, or Service and any helper code that isn't imported through composer or is systemwide available should be present inside this folder.

Make sure that the src-folder is mentioned in the 'autoload'-section of the composer.json file.

"autoload": {
    "psr-4": { "Graphit\\Examples\\": "src/" }
}

In case you use multiple namespaces and folders inside /src folder make sure to add multiple entries for all the folders and namespaces. For example:

"autoload": {
  "psr-4": {
    "Graphit\\Examples\\": "src/Examples",
    "Graphit\\Testing\\": "src/Testing"
  }
}

Make sure to read up on PSR-4 to avoid confusion.