metamask-extension/app/manifest/v3/chrome.json

{
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; frame-ancestors 'none';"
  },
  "externally_connectable": {
    "matches": ["https://metamask.io/*"],
    "ids": ["*"]
  },
  "minimum_chrome_version": "80"
}