Examine source code of City Lightning

{
  "name": "City Lightning",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "CityLightningH.jpg"
    },
    "colors": {
      "frame": "rgba(51, 11, 66, 1)",
      "tab_background_text": "rgba(250, 200, 246, 1)",
      "toolbar": "rgba(52, 11, 66, 0)",
      "bookmark_text": "rgba(250, 200, 246, 1)",
      "toolbar_field": "rgba(52, 11, 66, 0.08)",
      "toolbar_field_text": "rgba(250, 200, 246, 1)",
      "tab_line": "rgba(250, 200, 246, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{68857ca6-d9ae-42aa-b2a2-1d3a969ee8aa}"
    }
  }
}