Examine source code of Philadelphia Skyline

{
  "theme": {
    "images": {
      "theme_frame": "skyline-crop.jpg"
    },
    "colors": {
      "frame": "#d63b1c",
      "tab_background_text": "#0e6c7d"
    }
  },
  "version": "2.0",
  "name": "Philadelphia Skyline",
  "manifest_version": 2
}