OptionalfreshnessOptionalofflinethe path, or a :name pattern; every path a pattern matches shares the one version
OptionalsyncWhat the file is at now: a content hash (sha256-<base64>, also sha384- and sha512-),
an entity tag ("abc"), or any label. A hash and a tag are checked against the bytes
fetched; a label is trusted. A changed value drops the stored copy.
one file a site serves as is and the worker may keep