Examine source code of Starry Nightfall

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Starry Nightfall",
  "manifest_version": 2,
  "description": "Source image: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/54e8cb8ab585fac4f33699db94c4bcb6c41a2399b10dc6b25000c5f1684bc80d/https%3A//pixabay.com/en/stars-constellation-sky-night-sky-1245902/\">https://pixabay.com/en/stars-constellation-sky-night-sky-1245902/</a>"
}