Examine source code of American Heritage

{
  "name": "American Heritage",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "AmericanHeritageH.jpg"
    },
    "colors": {
      "frame": "rgba(197, 216, 240, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(197, 215, 240, 0)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(197, 215, 240, 0.03)",
      "toolbar_field_text": "rgba(3, 3, 3, 1)",
      "tab_line": "rgba(166, 18, 18, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{71c2e185-9b9f-4cbd-ab85-8436fb4ffc99}"
    }
  }
}