# Configuration Overlay Rename

Status: implementation complete; release preparation remains separate.

ConfigKit now calls the selected configuration feature an overlay. The current
behavior is owned by the [selected-overlay contract](../config.md#selected-overlays),
and upgrade instructions are in the [consumer migration guide](../consumers/README.md#selected-overlay-migration).

The completed migration intentionally changed four breaking surfaces:

- Go API identifiers, including `Options.Overlay`, `LayerOverlay`, and
  `CodeOverlay*`;
- selected-file location to `overlays/<name>.yml` without a `profiles/` fallback;
- provenance layer value to `overlay`; and
- diagnostic-code strings to `overlay.*`.

Application-owned profile concepts, including `ModelProfile` and `model_profile`,
remain unchanged. A future v0.4.0 release-preparation task must describe all four
breaking surfaces. Versioning, release notes, tagging, publishing, dependency
updates, and downstream changes are not part of this completed implementation.