pdses that can't prove a record is absent answer the sparse probe with RecordNotFound or a bare 404, which sent every repo on them to a full getRepo. those now start from getLatestCommit and getBlocks(commit): the commit is trusted through its signature like a proof's, so the scan finds the same records with a couple more requests. the mst root is fetched up front so auto mode can still pick full for tiny trees. both the sparse and full paths now reject a commit that names another did.