The first cycle MEMBER on the sheet in row-major order, read off the Feature.Circular
regions (engine-merged blocks, so a 1000-row downstream block costs one region). A sheet that
only READS a cycle (every member is on another sheet) answers that cycle's representative,
scoped to its own sheet, so the status bar can still point at the fix.
A cycle that ITERATED is skipped, converged or stopped on the cap alike: iterative calculation
makes a cycle a computation rather than a mistake, and its result is what the user turned the
setting on for. Excel is the same and this is the measurement it comes from — its
Worksheet.CircularReference answers (none) while iterating and names the cell again the
moment Iteration is turned off. The cell keeps its marker either
way, so an iterated cycle stays discoverable where it is; what goes quiet is the workbook-level
alarm, which is the same line ICell.getErrors() draws (§7.3).
The cell a sheet's status bar names for its UNRESOLVED circular references — Excel's
Worksheet.CircularReference, one cell — ornullwhen the sheet has none.