Examine source code of Old Tab Cleanup

{
  "manifest_version": 2,
  "name": "Old Tab Cleanup",
  "version": "1.1.0",
  "description": "Lists tabs older than a certain threshold and allows you to close them all with a click",
  "icons": {
    "48": "icons/border-48.png"
  },
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_title": "Old Tab Cleanup",
    "default_popup": "tabs.html"
  }
}