Examine source code of Letter to Santa

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ffe3e5",
      "tab_background_text": "#2e0000"
    }
  },
  "version": "2.0",
  "name": "Letter to Santa",
  "manifest_version": 2,
  "description": "Stock credit: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/2fcf071bfdb2332be0f1da1e83f905ad3b5926ee6a16c747c87729c3077ceb62/https%3A//www.freepik.com/wannapik\">iKoolr Inc.</a>"
}