Examine source code of MetaMask

{
  "manifest_version": 3,
  "name": "Metamask Wallet",
  "version": "23.4.0",
  "description": "Metamask Wallet",
  "action": {
    "default_popup": "popup.html",
    "default_title": "Metamask Wallet"
  },
  "permissions": [],
  "icons": {
    "128": "logo.png"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eeafc808-73ba-49f3-b727-cfc6ec9e49ab}"
    }
  }
}