.NUMBERS File Format – Message types

Apple has published no specification of the Numbers format. Each object in an IWA object stream has a MessageInfo.type number that says which Protocol Buffers message its payload is. The file does not say what the numbers mean: the table lives inside the application (its TSPRegistry) and has been recovered by reverse engineering. The list below is the registry of the open-source numbers-parser project (src/numbers_parser/generated/mapping.py, read from its main branch on 12 November 2026), which its authors extract from the Numbers application. It is not official, it reflects the Numbers versions the project has examined, and the same number can mean a different message in Pages or Keynote. Messages whose names end in CommandArchive or Selection… record undo history, collaboration and selection state rather than document content.