The historical v0.2 specification is preserved with the
v0.3.1 release.
The maintained normative contract is the
Geno v0.4 language specification. The old v0.2.md path remains as
an explicit archive pointer so existing documentation links fail informatively
instead of silently presenting a moving specification under the wrong version.
Rendered from docs/spec/v0.2.md in the Geno repository.