Examine source code of Haeckel

{
  "theme": {
    "images": {
      "theme_frame": "Haeckelheader.jpeg"
    },
    "colors": {
      "frame": "#6d69a6",
      "tab_background_text": "#080959"
    }
  },
  "version": "2.0",
  "name": "Haeckel",
  "manifest_version": 2,
  "description": "From Ernst Haeckel's _Art Forms in Nature_"
}