Check a receipt yourself
Load a receipt you downloaded from Arena. This page checks it on your device and makes no network request: not to Arena, not to anyone.
It proves one thing: that exact call existed before kick-off, because an independent timestamp authority signed it then.
What is checked
1. The sealed call text hashes (SHA-256) to the receipt's hash, so not a digit of it changed.
2. That hash is a line of the batch manifest, and the manifest hashes to the batch digest.
3. The timestamp authority's signature over that digest verifies, and its time is before kick-off.
4. Compare the signing certificate's fingerprint with the one the authority publishes, or load its certificates above.
Prefer the command line? Run node scripts/check-receipt.mjs receipt.json from Arena's public source, or openssl ts -verify as the receipt explains.