[
  {
    "source": "file.css",
    "warnings": [
      {
        "line": 1,
        "rule": "color-no-invalid-hex",
        "text": "external issue message (color-no-invalid-hex)"
      },
      {
        "line": 1,
        "rule": "comment-no-empty",
        "text": "external issue message (comment-no-empty)"
      }
    ]
  }
]