---
okf_version: "0.2"
---

# ONS data discovery OKF

This is the canonical OKF v0.2 entrypoint for a bounded, metadata-only ONS discovery snapshot. It contains no statistical observation values.

# Knowledge concepts

* [Catalogue and extension entrypoints](concepts/catalogue.md) - the metadata catalogue and its large-corpus Explorer projection.
* [Governed frozen snapshot](concepts/snapshot.md) - snapshot identity, coverage and freshness boundary.
* [Source lanes](concepts/sources/) - the four bounded metadata sources.
* [Provider snapshot/live datapack](concepts/provider-datapack.md) - the dated reviewed-live distinction.
* [Governance](concepts/governance.md) - authority, integrity and non-endorsement boundaries.
* [Standards evidence](concepts/standards.md) - structural OKF v0.2 conformance and other evidence mappings.
* [MCP selection contract](concepts/mcp-selection.md) - non-executing selection metadata.

# Compatibility and extensions

The Markdown concepts are the portable OKF core. [`okf-explorer.json`](okf-explorer.json), YAML-LD, JSON-LD, static search, facets, federation, integrity files and provider datapacks are additive extensions. Concept documents retain the legacy `timestamp` and `# Citations` forms for best-effort v0.1 consumers; v0.2 consumers must prefer `generated` and `sources`.