Drop in a passport or a demo trace. The file is read in this browser and never uploaded — the public key is fetched separately and the check runs on your machine, because a verification we performed for you would just be us vouching for ourselves.
Prefer to check it offline? The public key and the three-step procedure are in the documentation. Nothing here is required — this page exists to save you writing Ed25519 code, not to sit between you and the answer.