Examine source code of Beholder

{
  "theme": {
    "images": {
      "theme_frame": "BeholderHeader.jpg"
    },
    "colors": {
      "frame": "#a8a8a8",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Beholder",
  "manifest_version": 2,
  "description": "My second persona, made from my own source image."
}