How to trace

This TO is the reference for what GBO builds, the reasons for it, and the points that are open. From any kind of information in the TO, you can follow the chain to the other kinds. The TO connects five kinds of information:

Kind	ID	Question it answers	Where
Architecture decision	ADR-NNNN	What did the GBO team choose, and which alternatives did it refuse?	Decision log
Requirement	REQ-NN, RL-NN, AV-NN, BSNK-NN	What must the result do, and how does a test check it?	Requirements
Demo increment	SL-NN	Which demo work proved it, and with which PRs?	Demo increments
Finding	F-NN	What did the demo build show about the design?	Open findings, closed findings
Open question	Q-NN	What must another forum decide, and what does the TO assume until then?	Open questions, answered questions

Two more pages support the chain:

• The design to demo matrix takes each element of the GO, the PSA, FR-DvTP v0.9, and the EUDI regulation. For each element, it records whether the demo covers it.
• Standards feedback lists the open points in ETSI TS 119 478 (E1 to E10) that the ASI route found.

The chain

graph LR ADR[Architecture decision<br/>ADR-NNNN] -->|serves| REQ[Requirement<br/>REQ / RL / AV / BSNK] REQ -->|proved by| SL[Demo increment<br/>SL-NN + demo PRs] SL -->|exposed| F[Finding<br/>F-NN] F -->|lands in| REQ F -->|lands in| ADR F -->|needs a decision| Q[Open question<br/>Q-NN] Q -->|blocks| ADR ARC[arc42 section<br/>building blocks, runtime, concepts] -->|explains| ADR ARC -->|explains| SL %% GBO diagram palette: the same colors as the Globaal Ontwerp classDef basis fill:#DCFCE7,stroke:#16A34A,color:#0F172A classDef dvtp fill:#FEDCD8,stroke:#E28F80,color:#1E293B classDef eudi fill:#FFEDD5,stroke:#EA580C,color:#0F172A classDef source fill:#DDEBF7,stroke:#6F94B8,color:#1E293B classDef ext fill:#F1EFE8,stroke:#5F5E5A,color:#444441 classDef store fill:#EDE9FE,stroke:#7C3AED,color:#1E1B4B classDef mock fill:#F3F4F6,stroke:#9CA3AF,color:#374151,stroke-dasharray:4 3 classDef planned fill:#FFFFFF,stroke:#9CA3AF,color:#6B7280,stroke-dasharray:6 4 classDef zoom stroke-width:3px class ADR,REQ,SL,F,Q store class ARC ext

Each kind of item in the chain carries these links:

• A decision serves one or more requirements. An accepted decision has evidence in the demo. A proposed decision waits for an open question.
• A requirement names its source, its addressee, and its evidence in the demo. The source is the GO, the PSA, FR-DvTP, or the demo itself.
• A demo increment is a bounded piece of demo work. It names its demo PRs and the requirements, findings, and questions that it produced.
• A finding names its trigger, what it showed, and where it landed: a requirement, a decision, a risk, or an open question.
• An open question names the forum that must answer it. It also names the working assumption that the demo and this TO use until then.

Every arc42 page and every ADR ends with a Traceability section. That section lists the IDs that the page explains or depends on.

Start points

The first step depends on where you start:

You start at	Do this
A part of the demo	Find the component in the building block view or the flow in the runtime view. Its Traceability section names the decisions, requirements, and increments.
A demo increment	Open its entry in Demo increments. Explained in links the TO section. Produced links the requirements, findings, and questions.
An open finding	Open its entry in Findings. Read the summary first. The block Evidence, impact and proposal links the requirement, decision, or question. Coverage lists every page that cites the finding.
An open question	Open its entry in Open questions. The summary gives the question and the working assumption. The block below it names the forum that decides. Coverage lists the decisions that the question blocks.
A decision	Read the ADR. Coverage shows its full chain in one row.
A requirement	Open it from the list of all requirements. Evidence links the demo test or code. Coverage lists the pages that explain the requirement.

Example: the consumer has no citizen identifier

The chain for this example has six steps:

1. The runtime page DvTP query shows that the consumer sends a placeholder. After the allow, the source gateway puts the source's own value in place of the placeholder.
2. The decision is ADR-0033, with the consent proof in ADR-0032.
3. The decision serves REQ-21, REQ-79, and REQ-80.
4. The demo work is increment SL-51, with its demo PRs.
5. Three findings are open against the decision:
   • F-76: what the consumer records about "this person".
   • F-77: the PDP checks that the subject comes from the proof. The PDP does not check who the subject is.
   • F-79: "after the decision" holds only if nothing but the Inway reaches the gateway.
6. One decision waits: who is the BSNk participant (Q-49)? The proposed ADR-0040 records the working assumption (route D).

Baseline and maintenance

• Demo baseline: gbo-demo v0.9.0 (November 2, 2026). Links to demo code use this tag. A few historical evidence links pin an earlier demo commit.
• Status of the registers: November 2, 2026. On that date, 34 findings and 61 open questions are open or partly answered.
• Numbers: numbers are never reused. A withdrawn or removed requirement keeps its line in the list of removed numbers.
• When the demo changes: make these four updates:
  1. Update the requirement Evidence.
  2. Add or close findings.
  3. Update the increment.
  4. Update the Traceability section of the pages that explain the change.
• Generated page: scripts/gen_traceability.py generates Coverage. CI runs the script with --check. The script fails in two cases:
  • A page links an ID that no register defines.
  • No TO page or decision cites an open finding or an open question.