Examine source code of Poseidon Playground

{
  "theme": {
    "images": {
      "theme_frame": "hdposiden.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Poseidon Playground",
  "manifest_version": 2,
  "description": "Firefox Persona version of my “Poseidon's Playground” wallpaper.\n\n3D artwork by Ryan Bliss.\n\nPersona Designed by Mark Hamilton for Digital Blasphemy.\n\nWallpaper available at <a href=\"https://outgoing.prod.mozaws.net/v1/bd5a61f815ac2175c1b8b66ae612db49106939fd9bf0d25d6b7174ccef3a208d/http%3A//digitalblasphemy.com/preview.shtml%3Fi=poseidon1\" rel=\"nofollow\">http://digitalblasphemy.com/preview.shtml?i=poseidon1</a>"
}