Examine source code of Swirly Afterglow

{
  "theme": {
    "images": {
      "theme_frame": "SwirlyAfterglowH.JPG"
    },
    "colors": {
      "frame": "#363533",
      "tab_background_text": "#fafafa"
    }
  },
  "version": "2.0",
  "name": "Swirly Afterglow",
  "manifest_version": 2,
  "description": "The most spectacular sunset I've ever seen!"
}