Examine source code of Tab History Manager

{
  "manifest_version": 3,
  "name": "Tab History Manager",
  "version": "1.0",
  "description": "View and search through the history of closed tabs and restore them easily.",
  "icons": {
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{550e8400-e29b-41d5-a716-446655440000}"
    }
  },
  "permissions": [
    "sessions",
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "128": "icons/icon128.png"
    }
  }
}