curl --request GET \
  --url https://app.dynamicauth.com/api/v0/sdk/{environmentId}/users/mfa/register/passkey \
  --header 'Authorization: Bearer <token>'

{
  "id": "95b11417-f18f-457f-8804-68e361f9164f",
  "type": "totp",
  "registration": {
    "rp": {
      "name": "An example name",
      "id": "An example name"
    },
    "user": {
      "id": "An example name",
      "name": "An example name",
      "displayName": "An example name"
    },
    "challenge": "An example name",
    "pubKeyCredParams": [
      {
        "alg": 123,
        "type": "public-key"
      }
    ],
    "attestation": "direct",
    "timeout": 123,
    "authenticatorSelection": {
      "authenticatorAttachment": "cross-platform",
      "requireResidentKey": true,
      "residentKey": "discouraged",
      "userVerification": "discouraged"
    },
    "excludeCredentials": [
      {
        "id": "<string>",
        "type": "public-key"
      }
    ],
    "extensions": {
      "appid": "<string>",
      "credProps": true,
      "hmacCreateSecret": true
    }
  }
}