CLOSED 2026-09-23 (claude-code): Field.ParentID on ContentType.Task (Parts.xml); the indented view is SPF.2.
No task type in this platform has any parent link, so follow-up work cannot hang under the task that spawned it. SharePoint's Tasks list has ParentID, a Lookup to its own list, and an indented view over it. Borrow the real field name. Note the related debt in ProjectTask: its ProjectCode is declared FieldType Text rather than a Lookup, a cross-reference that no engine joins - promotion was deferred to V12.8b and never shipped.