ReadonlyrowFields on the Rows shelf, in shelf order.
ReadonlycolumnFields on the Columns shelf, in shelf order.
ReadonlyactiveReadonlymarksOne entry per marks card. A dual-axis worksheet has more than one, and nothing in the contract says which axis a card belongs to, whether the axes are synchronized, or how the cards are ordered.
A worksheet's visual specification: the shelves and the marks cards behind what was drawn.
Mirrors
VisualSpecificationinExternalContract/Shared/VisualModelInterface.d.ts. Every member is required, andreader.tsstill feature-detects the call that returns it — see TableauWorksheet.getVisualSpecificationAsync for why those two facts sit together.When it is present it is the only direct evidence of what chart the author drew; without it the extractor falls back to its heuristic ladder.
activeMarksSpecificationIndexis declared as a barenumberwith no documentation at all: nothing says it is integral, non-negative, or less thanmarksSpecifications.length. The extractor range-checks it rather than indexing with it.