Examine source code of Red Blob

{
  "theme": {
    "images": {
      "theme_frame": "RebBlobHCustom.jpg"
    },
    "colors": {
      "frame": "#e60909",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Red Blob",
  "manifest_version": 2,
  "description": "abstract, modern, red, splash, flower, spatter, \n\nDesigned by MaDonna\n\nMy wallpaper to match is at: <a href=\"https://outgoing.prod.mozaws.net/v1/19aae53418c7b9218d565e6c6ea2cfa4c88285b368e9a60efeae4359595d9c99/http%3A//abstract.desktopnexus.com/wallpaper/1033775/\" rel=\"nofollow\">http://abstract.desktopnexus.com/wallpaper/1033775/</a>"
}