Examine source code of Page Stat

{
  "name": "Page Stat",
  "version": "1.0.1",
  "description": "Display time usage statistics for accessed pages",
  "manifest_version": 2,
  "permissions": [
    "tabs",
    "storage",
    "unlimitedStorage",
    "alarms",
    "https://www.google.com/"
  ],
  "options_ui": {
    "page": "view/options/options.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "background_scripts/host.js",
      "background_scripts/page.js",
      "background_scripts/utils.js",
      "background_scripts/validator.js",
      "background_scripts/listeners_runtime.js",
      "background_scripts/listeners_tabs.js",
      "background_scripts/core.js",
      "background_scripts/alarm.js"
    ]
  },
  "browser_action": {
    "default_title": "Page usage statistics",
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "pagestat_by_pvpscript@github.com"
    }
  }
}