Examine source code of On a Rocky Island

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#943737",
      "tab_background_text": "#f5ebeb"
    }
  },
  "version": "2.0",
  "name": "On a Rocky Island",
  "manifest_version": 2,
  "description": "A rocky coast at some place of the eastern coast of Atlantic Ocean"
}