Examine source code of Colorful Spheres

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Colorful Spheres",
  "manifest_version": 2,
  "description": "Source image: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/fa493a822127b76c61725a918d056c51a6af81171e7b2e2dc0dba8d23d8cf9ac/https%3A//pixabay.com/en/ball-abstract-pattern-lines-443853/\">https://pixabay.com/en/ball-abstract-pattern-lines-443853/</a>"
}