Examine source code of Window Saver v1.7

{
  "manifest_version": 2,
  "name": "Window Saver",
  "description": "Save Windows to visit them later.",
  "version": "1.8",
  "icons": {
    "48": "icons/dark.png",
    "96": "icons/dark.png"
  },
  "browser_action": {
    "default_title": "Window Saver",
    "default_popup": "index.html",
    "default_icon": {
      "16": "icons/dark.png",
      "32": "icons/dark.png",
      "64": "icons/dark.png",
      "128": "icons/dark.png"
    },
    "theme_icons": [
      {
        "size": 16,
        "light": "icons/light.png",
        "dark": "icons/dark.png"
      },
      {
        "size": 32,
        "light": "icons/light.png",
        "dark": "icons/dark.png"
      },
      {
        "size": 64,
        "light": "icons/light.png",
        "dark": "icons/dark.png"
      },
      {
        "size": 128,
        "light": "icons/light.png",
        "dark": "icons/dark.png"
      }
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "bookmarks",
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  }
}