Examine source code of The Danse Macabre

{
  "theme": {
    "images": {
      "theme_frame": "danse_macabre-header.jpg"
    },
    "colors": {
      "frame": "#885c34",
      "tab_background_text": "#f5e198"
    }
  },
  "version": "2.0",
  "name": "The Danse Macabre",
  "manifest_version": 2,
  "description": "The Dance of Death, a horror on your browser just in time for Halloween."
}