Examine source code of Horse Herd

{
  "name": "Horse Herd",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "horseherd.jpg"
    },
    "colors": {
      "frame": "rgba(166, 178, 207, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(135, 85, 27, 0.07)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d8e5c405-4862-4984-b76e-a75c0f42546c}"
    }
  }
}