Examine source code of The Cake Lied

{
  "theme": {
    "images": {
      "theme_frame": "Header3.png"
    },
    "colors": {
      "frame": "#000",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "The Cake Lied",
  "manifest_version": 2,
  "description": "We all know it, it had to be done, Portal is owned by Valve Corporation and I claim no ownership of images or that, but all are free to use."
}