Glossary of Excel package and Open XML terms
These are the package and formula terms the checks use. Each one points at the tool that measures it and the guide that explains what to do next.
Open XML package
A modern Excel workbook is a ZIP package of XML parts, not a single binary blob. workbook.xml lists sheets, relationships point at those parts, and [Content_Types].xml tells Excel what each part is. If any of those disagree, Excel reports unreadable content. The corruption checker tests that agreement. It does not rewrite the package.
Used range
The used range is the rectangle Excel believes a sheet occupies. It is stored as the dimension element, for example A1:XFD1048576. It should end near the last real value. When it does not, Ctrl+End jumps into empty space and the file keeps a phantom grid. The used-range checker compares that declaration with the last cell that actually holds a value or formula.
Pivot cache
A PivotTable on a sheet is a view. The pivot cache is the stored copy of the source rows, usually under xl/pivotCache. The records part is why a small-looking pivot can dominate file size. saveData and refreshOnLoad live on the cache definition. The cache checker reads those flags and the size of the records.
Volatile function
A volatile function is eligible to recalculate on edits that do not change its inputs. NOW, TODAY, RAND, RANDBETWEEN, OFFSET, INDIRECT, INFO, and CELL are the eight names this site counts. INDEX and the lookup functions are not in that list. A header with one TODAY is ordinary. A sheet of OFFSET formulas is a calculation problem.
Defined name
A defined name is a label in workbook.xml that points at a formula, such as a range, a broken #REF!, or another workbook. Names can be hidden or local to one sheet. Names beginning with _xlnm are Excel’s own print areas and filters. The name auditor lists them and marks broken, external, and unused candidates.
External link
An external link is a stored path to another workbook. It lives in xl/externalLinks and in formulas or names that use a bracketed file name. Edit Links does not always show every one of them, which is why Break Links can appear to do nothing. The link finder lists the stored targets and does not try to open them.
vbaProject.bin
vbaProject.bin is the compound file inside a macro-enabled workbook that holds the VBA project. Its presence means the file can contain macros. Module names can be read from the PROJECT stream. Auto-start names such as Workbook_Open can be detected as text. None of that is a virus scan, and a missing project is not a general safety certificate.
Conditional formatting rule
A conditional formatting rule is stored on the worksheet as a cfRule inside a conditionalFormatting element. The sqref attribute lists the ranges it covers. One rule for a column is cheap. The same look applied cell by cell becomes hundreds of rules and a larger styles part. The formatting checker counts rules, ranges, and dxf records.
Cached cell error
A cached cell error is an error value Excel stored after calculation, such as #REF!, #VALUE!, or #N/A, on a cell marked as an error. The error finder reads those stored values and their addresses. It does not recalculate the workbook, so it reports the file you saved, not a hypothetical next refresh.
BIFF12
BIFF12 is the binary worksheet format inside an .xlsb package. The file is still a ZIP, so part sizes, sheet names, and sheet visibility can be read. Formula text is not XML, so this site’s formula, name, and error checks do not run on it yet. Legacy .xls is BIFF8, a different container, and is not supported.