curl --request GET \
  --url https://hub-api.neynar.com/v1/userNameProofsByFid \
  --header 'x-api-key: <api-key>'

{
  "proofs": [
    {
      "timestamp": 123,
      "name": "neynar",
      "owner": "<string>",
      "signature": "aSDinaTvuI8gbWludGxpZnk=",
      "fid": 1,
      "type": "USERNAME_TYPE_FNAME"
    }
  ]
}