Examine source code of Groningen Skyline

{
  "theme": {
    "images": {
      "theme_frame": "Groningen_skyline_header.png"
    },
    "colors": {
      "frame": "#4f4d4d",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Groningen Skyline",
  "manifest_version": 2,
  "description": "Skyline Persona of the most beautiful city in the Netherlands. \n\n(Photo was posted by Maok on the <a href=\"https://outgoing.prod.mozaws.net/v1/92092664b2ca2089e642a95cb4abeb8d27533d2af1edeffbf6190abee1590473/http%3A//fok.nl\" rel=\"nofollow\">fok.nl</a> forum)"
}