4.2 The registry and the cache
The built-in interop-identities registry is a small embedded OCIO config carrying the published ID set — one authoritative, release-pinned statement of what lin_ap1_scene means, usable from any user config on any supported OpenColorIO version. It is consulted internally (lookup only, never a substitute for the user’s config), and it is pinned per release rather than following “latest,” because identification results must not drift between two builds of the same software.
The cache is the registry’s quiet twin, and the contract everything else rides on: every process-global memo keys on OpenColorIO’s own config cacheID (plus context where applicable). Content-addressed, no invalidation — which works only because configs are immutable after construction; any repair produces a modified copy, memoized under the source config’s ID, never mutation in place. Expensive results (identification probes, computed color-space properties) are therefore paid once per config, not once per file.