Examine source code of Container Tab Flow

{
  "manifest_version": 3,
  "name": "Container Tab Flow",
  "description": "Stay within the current container when closing a tab",
  "version": "1.0.4",
  "author": "Maxim Baz <containertabflow@maximbaz.com>, ChatGPT by OpenAI <contact@openai.com>",
  "homepage_url": "https://github.com/maximbaz/container-tab-flow",
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "containertabflow@maximbaz.com"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  }
}