Examine source code of Recent Tabs Sort

{
  "manifest_version": 3,
  "name": "Recent Tabs Sort",
  "version": "2.4.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "RecentTabs@bigbrainindustries.com"
    }
  },
  "description": "keeps your tabs sorted by most recently used.",
  "homepage_url": "https://github.com/BigBrain-Industries/recent-tabs/tree/master",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  },
  "action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Recent Tabs",
    "default_popup": "popup/settings.html"
  },
  "options_ui": {
    "page": "popup/settings.html"
  }
}