Member Junction
    Preparing search index...
    WellKnownField:
        | "Text"
        | "FileType"
        | "ContentType"
        | "Title"
        | "Date"
        | "Modality"
        | "Decorator"

    The fields that map onto real columns. Anything a stage wants persisted is one of these; anything only a later stage in the same run needs goes in the extension space.