Examine source code of Classic Windows

{
  "name": "Classic Windows",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "Classic Windows (Final Version).png"
    },
    "colors": {
      "frame": "rgba(192, 192, 192, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(0, 0, 128, 1)",
      "toolbar_field": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4a5179a3-39d1-490e-8511-c0aaf3418315}"
    }
  }
}