Examine source code of Hidden City by M♥Donna

{
  "name": "Hidden City by M♥Donna",
  "manifest_version": 2,
  "version": "5.0",
  "theme": {
    "images": {
      "theme_frame": "LakesideCityH.jpg"
    },
    "colors": {
      "frame": "rgba(38, 34, 17, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(38, 34, 17, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(38, 34, 17, 0.03)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0143cbf0-1d7b-411f-bb9a-80a41d39a7ed}"
    }
  }
}