Examine source code of Nesting Swan

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Nesting_Swan_top.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Nesting Swan",
  "manifest_version": 2,
  "description": "My photo of a nesting swan. More photos at <a href=\"https://outgoing.prod.mozaws.net/v1/c8f35d8d5199f35bca5ba66e8ef6a123383ca95cb1f25dd805e7a1d3b4b49443/http%3A//mixeriksson.com\" rel=\"nofollow\">http://mixeriksson.com</a>."
}