The format types artifacts by structure, and repo-state 4.4 exempts only what a parser declines to classify -- so a stored blob whose bytes are a valid check-in manifest IS a check-in, joins the DAG, and may carry its own branch tags. A repository tracking such a file (a Fossil-to-Git mirror's 'manifest' is the common source) therefore holds check-ins of another repository, whose blobs it never had. That derivation is conformant; Fossil does the same.

What was not acceptable was spending minutes materializing before finding out, then reporting it as a missing file with no way to see why. open now presence-checks the resolved tip's file set before invoking the engine and refuses naming the class; update prints the same explanation.

Advisory only: a files() fault falls through, and stagePlan remains the sole authority, so this cannot let anything through -- it can only refuse earlier. Verified against a foreign self-tagged manifest that genuinely hijacks trunk: exit 1, working tree untouched. (#42) check-in: a81e9a8745 user: dmestas tags: sub-manifest