General General PDSEdit layer objects.
 PDSAttrObjA PDSAttrObj represents a structure attribute object, which is a Cos dictionary or stream describing attributes associated with a PDSElement. The attribute's data may be application-specific, suiting the application that adds or extracts logical structure information. An attribute object can have a revision number to indicate whether other applications have modified either the associated element or the element's contents since the application created or modified the element.
 PDSClassMapThe PDSClassMap (or class map) associates class names with a set of attribute objects. A structural element may have a list of names identifying the classes to which it belongs. Associated attributes are shared by all structural elements belonging to a given class. There is only one class map per document, associated with the PDSTreeRoot.
 PDSElementPDSElement is the basic building block of the structure tree. It represents PDF structural elements, which are nodes in a tree, defining a PDF document's logical structure.
 PDSMCPortions of a page's contents may be wrapped with marked content operators. A PDSMC object represents this marked content. A tag and an optional property list may be associated with a PDSMC. PDSMC is identical to the PDFEdit class PDEContainer. PDSMC objects may be nested.
 PDSOBJRAn object reference (OBJR) is a reference to a PDF object. A PDSOBJR object references an entire Cos dictionary or stream.
 PDSRoleMapEach structure element must have a structure type. The definition of such types is application-specific. In addition, PDF 1.3 defines a standard set of structure types for logical structure in PDF documents. The role map (PDSRoleMap) maps application-specific element types to the standard element types that have a similar function. There is only one PDSRoleMap per document, associated with the PDSTreeRoot.
 PDSTreeRootAll logical structure information is in the structure tree, and the PDSTreeRoot is its root. There is at most one PDSTreeRoot in each document.