Examine source code of Dark night 2

{
  "name": "Dark night 2",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "blick in die stad.jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(0, 84, 158, 1)",
      "toolbar": "rgba(0, 15, 51, 1)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(0, 0, 0, 1)",
      "toolbar_field_text": "rgba(0, 87, 217, 1)",
      "tab_line": "rgba(0, 0, 0, 0.57)"
    }
  }
}