POPCORN Contribution License 1.0

This license accompanies a POPCORN witness receipt identified by its Temporal
Anchor Issuance Number (TAIN). The receipt is evidence that a payload digest
was witnessed at a stated time by a stated node. It is not a token, credit,
identity credential, or authorization.

1. Attribution. Any system that presents, relays, or relies on the receipt
must attribute issuance to the POPCORN node named in the receipt's
issuing_origin, and must reproduce the TAIN unchanged.

2. Permitted use. The holder may use the receipt to prove that the digest it
commits to was witnessed at the stated time, to link it into a predecessor
chain, and to present it to counterparties, agents, or auditors. The holder
may copy and transmit the receipt freely.

3. Prohibited use. The holder may not alter any signed field, present the
receipt as proof of caller identity, delivery, execution, truth, legality, or
permission, or represent the receipt as an authorization or instruction.

4. Success threshold and payment trigger. The witness fee is earned when the
node returns a signed receipt for a settled payment. No further performance
is promised. Payment for the witness service is triggered by the x402
settlement that precedes issuance; the receipt is the deliverable.

5. Calculation. Fees are denominated in USDC on the network named in the
receipt's payment context. The amount due per issuance is the amount
advertised by the node at the issuance endpoint at the time of the request.

6. Exit. The holder may stop using the receipt at any time. The node may
rotate its signing keys and publish revocation or key-compromise notices at
its well-known key location. Verification against a rotated or revoked key
is the verifier's responsibility under its local policy.

This is a draft instrument, not legal advice. Questions of enforceability
are the reader's own.