Examine source code of HOCHTIEF - Black

{
  "name": "HOCHTIEF - Black",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "Firefox Hochtief Header Black.png"
    },
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0.15)",
      "frame": "rgba(23, 24, 28, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)"
    }
  }
}