Examine source code of skull5

{
  "name": "skull5",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "skull5.png"
    },
    "colors": {
      "frame": "rgba(28, 28, 28, 0)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(15, 15, 15, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(255, 255, 255, 1)",
      "toolbar_field_text": "rgba(168, 3, 0, 1)"
    }
  }
}