Examine source code of KINGification Youtube

{
  "manifest_version": 3,
  "name": "KINGification Youtube",
  "description": "Ajoute King dans les miniatures Youtube",
  "version": "1",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "host_permissions": [
    "https://www.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "KINGification.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "images/*.png"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "kingification@mrsupereggman.extensions",
      "strict_min_version": "109.0"
    }
  }
}