Examine source code of Cardboard

{
  "theme": {
    "images": {
      "theme_frame": "CardboardPersonaTop.jpg"
    },
    "colors": {
      "frame": "#968b8b",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Cardboard",
  "manifest_version": 2,
  "description": "It's just a Persona about cardboard. I wanted one, searched, but couldn't find one. It's not very good, someone with any real editing skills should recycle my cardboard and make a good one.\nSupport recycling!\nSalut."
}