OptionalactionWhether this format applies formatting or represents a blank override.
The pivot table region this format applies to.
OptionalstyleThe formatting to overlay on the area's cells. Only the properties present apply; everything
else on a cell is left as-is (the differential-format semantics of OOXML's dxf).
Absent for action: 'blank'.
A custom format applied to a specific region of a pivot table.
Each format pairs a pivotArea that defines which cells the format targets with an action indicating whether formatting is applied or blanked.
Formats are the durable representation of user formatting on pivot output: a consumer re-resolves each format's area against the current layout and overlays its style on every repaint, so the formatting follows the targeted region (an item's data cells, the grand total row, ...) when the pivot reshapes, rather than sticking to cell coordinates.