Examine source code of Blue skull theme

{
  "name": "Blue skull theme",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "Blue skulls.png"
    },
    "colors": {
      "frame": "rgba(27, 59, 80, 1)",
      "tab_background_text": "rgba(162, 176, 219, 1)",
      "toolbar": "rgba(31, 40, 43, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(33, 42, 46, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(162, 176, 219, 1)"
    }
  }
}