Examine source code of Chat creator

{
  "manifest_version": 3,
  "name": "Сhat creator",
  "version": "1.0.0",
  "description": "Extension for creating WhatsApp and Telegram chat with unknown phone number",
  "author": "Евдокимова В.А.",
  "browser_specific_settings": {
    "gecko": {
      "id": "chatcreator@uteams.ru"
    }
  },
  "icons": {
    "16": "icons/chat.png",
    "32": "icons/chat.png",
    "48": "icons/chat.png",
    "128": "icons/chat.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "scripting",
    "clipboardRead"
  ],
  "background": {
    "scripts": [
      "service-worker.js"
    ]
  },
  "action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "injected.js"
      ],
      "run_at": "document_start",
      "world": "MAIN"
    },
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "whats.js"
      ],
      "run_at": "document_start"
    }
  ]
}