Proposal: <title>

One page. A proposal that needs more than a page is two proposals. GOVERNANCE.md says which changes need one: a new schema, a field whose meaning is not obvious from its name, a narrowing rule or refusal code, a reserved vocabulary, a change to what the corpus checks, and anything that touches canonical bytes or signatures (which is a major version).

Summary

What changes, in two sentences.

Motivation

What cannot be expressed, checked or agreed today. Name the artefact, journal line or implementation that shows it; the contract changes because of evidence, not because a field would be nice.

Design

The shape, rule or check, concretely: a field with its type and constraints; a rule with its code and the fixture that would refuse it; a vector with the grant or refusal it must produce. Patterns are ECMA-262 regular expressions in the subset that compiles under RE2 (no lookaround, no backreferences), applied as an unanchored search per JSON Schema, and must read the same under Python's re, RE2 and ECMAScript (the corpus runs under six validators).

Backward compatibility

Answer the additive rule: a new optional field or vocabulary member (additive), a tightening (with the evidence that no conformant writer ever produced what it refuses, and the allow-list entry that will name it), or a 2.0 change (with the migration). Say which stability the field carries, stable or development, and why.

Security

What this lets into a permanent record (audit, signals, provenance, the lease journal), or out of a lease, that could not get there before. "Nothing" is an acceptable answer when it is true and the reason is given.

Alternatives

What else was considered and why not, including doing nothing.

Decision

Filled by the maintainer: accepted, rejected or superseded, with the reason, and the date.