A done key the controller never took in holds no manifest, and the store's nightly collector deleted its bare blob: node-tools', mesh-host's and the forge bridge's keys name blobs that answer 404. Since issue 1933 the take-in refuses such a key, and nothing built it again. held (in the serving process, HEADs only) lets the builder ask before it reuses a key; a refused take-in now names every gone archive and says artifacts-gone with the module, key, fingerprint and references.