Source Snapshot. The preserved, identifiable version of an evidence source used to ground a conclusion: source identity, content hash, fetch date, freshness state, evidence approval state, license or permitted use, and the cited excerpt or artifact reference.
A URL is not a source snapshot. A page can change, disappear, redirect, or become unavailable to a reviewer. A snapshot gives a conclusion something stable to point back to, so the evidence can be verified after the runtime moment is gone.
Source snapshots are the small units inside an evidence bundle. They support preserved derivation, inform source health, and make evidence eligibility reviewable instead of implied by retrieval success.