Examine source code of SearchEngineSwitcher

{
  "manifest_version": 3,
  "name": "SearchEngineSwitcher",
  "version": "2.1.1",
  "icons": {
    "16": "assets/icons/favicon-16.png",
    "32": "assets/icons/favicon-32.png",
    "48": "assets/icons/favicon-48.png",
    "128": "assets/icons/favicon-128.png"
  },
  "description": "Helps you switch between search engines quickly and easily.",
  "homepage_url": "https://github.com/StasJS/SearchEngineSwitcher/",
  "short_name": "SearchEngineSwitcher",
  "permissions": [
    "storage"
  ],
  "optional_permissions": [],
  "host_permissions": [
    "*://*.duckduckgo.com/*",
    "*://*.google.com/search*",
    "*://*.ecosia.org/search*",
    "*://*.bing.com/search*",
    "*://*.search.brave.com/search*",
    "*://*.yandex.com/search*"
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  },
  "author": "StasJS",
  "browser_specific_settings": {
    "gecko": {
      "id": "{a40e12fc-c713-4230-807a-8e84a658ec08}",
      "strict_min_version": "112.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "action": {
    "default_popup": "Popup/popup.html",
    "default_icon": {
      "16": "assets/icons/favicon-16.png",
      "32": "assets/icons/favicon-32.png",
      "48": "assets/icons/favicon-48.png",
      "128": "assets/icons/favicon-128.png"
    },
    "default_title": "SearchEngineSwitcher"
  },
  "background": {
    "scripts": [
      "assets/js/background.bundle.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "run_at": "document_end",
      "matches": [
        "*://*.duckduckgo.com/*",
        "*://*.google.com/search*",
        "*://*.ecosia.org/search*",
        "*://*.bing.com/search*",
        "*://*.search.brave.com/search*",
        "*://*.yandex.com/search*"
      ],
      "css": [],
      "js": [
        "assets/js/contentScript.bundle.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "assets/*"
      ],
      "matches": [
        "*://*.duckduckgo.com/*",
        "*://*.google.com/*",
        "*://*.ecosia.org/*",
        "*://*.bing.com/*",
        "*://*.brave.com/*",
        "*://*.yandex.com/*"
      ]
    }
  ]
}