Examine source code of Simple Hello

{
  "manifest_version": 2,
  "name": "Simple Hello Extension",
  "version": "1.0",
  "description": "A simple Firefox extension with no ID.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{0c01ada6-160c-4ea5-9cd4-0c4ba086b5e2}"
    }
  }
}