Data retention

Artefact bodies (counts.json, urandom.json, circuit.qasm, params.json) are kept 30 days, inside a 50 MB cap. When the cap nears, the oldest bodies are dropped first. Attempt metadata, the summary histograms and the sha256 of every file are kept forever, so an archived link reads "archived after 30 days · sha256 …" and any copy you saved can still be checked. See the Counts archive.