Examine source code of blacklight city

{
  "theme": {
    "images": {
      "theme_frame": "blacklightcity5.jpg"
    },
    "colors": {
      "frame": "#171515",
      "tab_background_text": "#f7efef"
    }
  },
  "version": "2.0",
  "name": "blacklight city",
  "manifest_version": 2,
  "description": "a white city on black background abstract"
}