[craigm26]

Description

Draft extension for discussion: solidarity lets a client attach a separately authorized share, at a rate its owner agreed to in advance, to an allow-listed humanitarian fund.

• Resource server is unaffected and never pays the share.
• Facilitators that support it list solidarity in /supported, settle the share apart from the purchase (a failed share never changes the purchase result), and report via EXTENSION-RESPONSES.
• Facilitators publish monthly RFC 6962 Merkle batches so owners can verify inclusion.

Open question for maintainers (in the doc): the share is the buyer's choice, so the server does not advertise it. Is a client adding an extension the server did not advertise, when the facilitator supports it, compatible with the v2 extension rules, or does that need a clarification?

Reference checker (Python stdlib), simulated ledger and allocation rule: https://craigmerry.com/solidarity-levy/

Drafted with Claude Code; I have read and reviewed the text. Opening as a draft for feedback before anyone spends review time on it.

Tests

Docs only. The Merkle construction in the doc reproduces the RFC 6962 reference vectors in both reference implementations (verify.py --selftest, merkle.js).

Checklist

• I have formatted and linted my code
• All new and existing tests pass
• My commits are signed (required for merge)
• I added a changelog fragment for user-facing changes (docs-only changes can skip)

🤖 Generated with Claude Code

https://claude.ai/code/session_01HVfVKz85T7urVZ6JnZ3A3E

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

[github-actions]

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