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 (DESIGN-CIRCULAR-CALC §2.4). 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.