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ADR-0016: License-Gated Reference Archive as a Pointer Registry

  • Status: Accepted
  • Date: 2026-07-03

Context

TODO.md's "Future Infrastructure" section proposed building "XwkOnt's own reference archive" once the public repository and ontology-core-v0.1.0 were live (both true as of 2026-07-03). As originally worded, the item described an XwkOnt-controlled mirror/snapshot of each cited source's content, addressable via a newly minted, XwkOnt-issued GUID per reference record, in addition to the DOI/Wayback Machine citation ADR-0012 already requires.

Reviewing that proposal surfaced a problem ADR-0012 did not have to face: ADR-0012's Memento/Wayback adaptation relies on the Internet Archive's own library/archival legal basis for hosting third-party copyrighted content. An XwkOnt-controlled mirror has no equivalent basis. Most of docs/references/ref-*.md's existing records carry unknown or unverified Rights/license values (journal articles, technical reports, project web pages); mirroring their full content on an XwkOnt-controlled host without a confirmed redistribution right would create real copyright exposure that DOI resolvers and the Internet Archive do not carry in the same way. Two records already have a verified, explicitly permissive license: ref-gfo.md (CC-BY-4.0) and ref-tupper-colore.md (CC-BY-SA-4.0).

Separately, docs/INFORMATION_ARCHITECTURE.md already defines a local identifier convention for reference records, xwkont:ref:<slug> (e.g. xwkont:ref:bfo-2020). The original TODO wording's "XwkOnt-issued GUID" would duplicate this without a stated reason.

Decision

XwkOnt adopts a narrower scope than the original TODO item:

  1. No general content-mirroring archive is built now. Full-content mirroring of a cited source requires that source's Rights/license field to be a verified, explicit license that permits redistribution (e.g. CC-BY, CC-BY-SA, or equivalent) before any local copy is made. unknown, unverified, or restrictive licenses are not mirrored, regardless of hosting readiness.
  2. No new identifier scheme is introduced. The existing xwkont:ref:<slug> local identifier (docs/INFORMATION_ARCHITECTURE.md) is reused as the pointer-registry key. A separate XwkOnt-issued GUID is not needed and is not created.
  3. docs/references/TEMPLATE.md gains one new Descriptive Metadata field, Archive mirror status, distinct from ADR-0012's Snapshot / Stable Identifier field:
  4. not applicable — license unknown or unverified (default; matches ADR-0012's existing "do not guess" posture),
  5. not applicable — license does not permit redistribution,
  6. eligible — license permits redistribution, not yet mirrored,
  7. mirrored — <path or URL> once an XwkOnt-controlled copy actually exists.
  8. Hosting location and domain remain deferred, exactly as the original TODO item already flagged (archive.xwkont vs. a w3id.org/xwkont/archive/ path is not decided by this ADR).
  9. This ADR does not itself mirror any content. It only defines the license gate and the record-level field. Marking ref-gfo.md and ref-tupper-colore.md eligible (their licenses are already verified permissive) and any actual mirroring remain future work.

Scope

This ADR amends docs/references/TEMPLATE.md's Descriptive Metadata table, adding one field. It does not change ADR-0012's DOI/Memento requirements, docs/INFORMATION_ARCHITECTURE.md's xwkont:ref:<slug> identifier convention, or any existing reference record's Snapshot / Stable Identifier value. Existing reference records are not required to be retrofitted with the new field immediately; unknown/default values are acceptable until a record is next touched, consistent with how ADR-0012's own retrofit list was handled.

Rationale

"Reuse Before Introduce" applies twice here: reusing xwkont:ref:<slug> instead of minting a new GUID scheme, and reusing each reference record's already-required Rights/license field as the gating signal instead of building a separate licensing-review workflow. Gating on verified license status, rather than building the archive first and sorting out rights later, avoids taking on copyright exposure the Internet Archive's Memento-based approach (ADR-0012) does not have to carry for the same content.

Consequences

Positive

  • No copyright risk is introduced: nothing is mirrored without a verified, explicit redistribution-permitting license.
  • No duplicate identifier scheme: xwkont:ref:<slug> already uniquely keys every reference record.
  • The two already-open-licensed sources (GFO, TUpper) give a concrete, low-risk starting point for eventual mirroring, once someone does the work.
  • Keeps the field addition small and reversible; does not commit to a hosting decision prematurely.

Trade-offs

  • This is a materially smaller deliverable than the original TODO item's "reference archive" — most current reference records (all but two) will show not applicable indefinitely unless their license is separately verified.
  • Citation permanence for unknown-license sources still depends entirely on DOI resolvers and Wayback snapshots (ADR-0012), not on any XwkOnt-controlled fallback. This ADR does not close that gap; it declines to close it via unauthorized mirroring.
  • A future maintainer wanting the originally envisioned full-content archive would need a separate licensing-review pass per source (contacting rights holders, or restricting scope to only permissively-licensed sources) — not something this ADR performs.

References

  • TODO.md ("Future Infrastructure" — reference archive item, original wording)
  • docs/adr/ADR-0012-adapt-doi-and-memento-for-reference-stability.md
  • docs/INFORMATION_ARCHITECTURE.md (xwkont:ref:<slug> identifier convention)
  • docs/references/ref-gfo.md, docs/references/ref-tupper-colore.md (currently the only verified-permissive-license reference records)