Examine source code of Goofy Halloween

{
  "name": "Goofy Halloween",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "rgba(255, 224, 156, 1)",
      "toolbar": "rgba(255, 255, 255, 0.08)",
      "bookmark_text": "rgba(255, 204, 226, 1)",
      "toolbar_field": "rgba(0, 0, 0, 0)",
      "toolbar_field_text": "rgba(217, 255, 191, 1)"
    }
  }
}