Examine source code of Tab Auto-Refresh Manager

{
  "manifest_version": 2,
  "name": "Tab Auto-Refresh Manager",
  "version": "1.0",
  "description": "Automatically refreshes/navigates to a specified URL every 60 seconds",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png",
    "default_title": "Tab Auto-Refresh Manager"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-auto-refresh@firefoxaddon.com",
      "strict_min_version": "79.0"
    }
  }
}