keepStructureTree property
Copies the structural tagging (tagged PDF: /StructTreeRoot, /MarkInfo
and the /StructParents of the pages).
Off by default because the tree is copied as it is: it keeps describing the document the source used to be. As long as the rewrite does not change content that is faithful, but any later edit of a page or of a content stream leaves the tagging out of date.
Implementation
final bool keepStructureTree;