OptionalClockClock-skew overlap subtracted from LastDiscoveredAt when computing Since, and subtracted from
walkStartedAt when Sync compares __mj_CreatedAt to spare concurrently created items. Default 60000 (60s).
OptionalMaxMost bytes an archive tree may expand to. No default, for the same reason.
OptionalMaxDeepest nesting an archive tree may reach (a .tar.gz is depth 2). Default 3.
OptionalMaxMost members an archive tree may unpack into. No default: an archive is refused rather than unpacked unbounded.
OptionalMaxMost characters an extractor returns for one block. Unset means no limit.
OptionalMaxHighest share of a source's live top-level items a Sync run may mark for deletion, 0–1. Default 0.5.
OptionalMinimumShare of a last-resort plain-text read that must be printable, 0–1. Default 0.85.
OptionalProgressHow often Discover reports progress, in items. Default 25.
The knobs a run may override. All optional.