Source controls
Safe failures remain part of the product.
Local-only
Workbook bytes are never sent to an application endpoint or retained after refresh.
Allowlisted
Only approved cells from six authoritative sheets enter the source pipeline.
Explicit periods
The review date and subject-specific periods replace unreliable runtime TODAY() selection.
Typed states
Zero, blank, N/A, unavailable, Excel errors, and missing cached results remain distinct.