Examine source code of Auto-Refresh

{
  "description": "Automatic refresh the current page at a time interval",
  "manifest_version": 2,
  "name": "Auto-Refresh",
  "version": "1.0",
  "homepage_url": "https://github.com/tks28/Auto-Refresh-WebExtension",
  "icons": {
    "48": "images/Refresh-icon-48.png",
    "128": "images/Refresh-icon-128.png"
  },
  "browser_action": {
    "default_popup": "autoRefresh.html",
    "default_icon": "images/Refresh-icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "http://*/",
    "https://*/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c8253ced-9a34-475f-afa1-4fd921534f15}"
    }
  }
}