The FORMAT SPECIFICATION — `stamp-format.md` and the example stamps under
`conformance/` — is licensed under the

    Creative Commons Attribution 4.0 International (CC BY 4.0)

    Human-readable summary: https://creativecommons.org/licenses/by/4.0/
    Legal code:             https://creativecommons.org/licenses/by/4.0/legalcode

Copyright 2026 Consiglio Nazionale delle Ricerche — Istituto di Scienze del
Patrimonio Culturale (CNR-ISPC).

WHY TWO LICENCES, AND WHERE THE LINE FALLS

The CODE in this repository — `dtcstamp.py`, `test_dtcstamp.py` and the
packaging around them — is under the Apache License 2.0; see LICENSE.

The SPECIFICATION is a document, not software, and it is meant to be quoted,
translated, republished in a paper and re-implemented in another language by
people who owe us nothing but the attribution. CC BY 4.0 says exactly that and
is the licence research infrastructures already recognise.

Apache-2.0 on the code is deliberate too: it is permissive enough that a
closed-source tool can vendor the module — which is the whole adoption
strategy — and it carries an explicit patent grant, which a bare MIT does not.

A note for anyone combining this with s3Dgraphy, which is GPL-3.0-or-later:
Apache-2.0 is one-way compatible with GPLv3, so GPLv3 software may depend on
this module. The reverse does not hold.
