Here is a list of all documented namespaces with brief descriptions:

[detail level 123456]

▼NiText
▼NPdf2Data
▼NExceptions
CInvalidResultException	Exception which is used by pdf2data on recognition result parsing for invalid result structure
▼NOcr
▼NEngine
▼CTesseract4BasedEngine	Engine which uses iText.Pdfocr.Tesseract4.Tesseract4LibOcrEngine as based ocr engine
CBuilder	Builder for Tesseract4BasedEngine
▼NResult
▼NMeta
CFontMetaResult	Class representing font metadata
CPageLocationMetaResult	Class representing page location metadata
▼NValue
▼NGroup
CGroupEntryResult	Class representing single group result's entry
CGroupResult	Class which represents group results
▼NTable
CTableCellResult	Class which represents single table cell result
CTableResult	Class which represents table result
CTableRowResult	Class which represents table row result
CAbstractValueResult	Common abstract parent for all possible results
CImageResult	Class which represents image result
CTextResult	Class representing text result
CUnknownResult	Class which representing unknown result type
CDataFieldResult	Class which represents data field result
CRecognitionResult	Class which represents recognition result
CIOcrEnginePostProcessor	Base interface for ocr post processors
COcrWithPostProcessingEngine	Engine which will apply post processors (if present) to results of base ocr engine
CPdf2DataExtractor	`Pdf2DataExtractor` is a class for extracting data from files
CPdf2DataTemplateConverter	Contains methods for creating p2dta
CRecognitionProperties	The `RecognitionProperties` class represents properties of recognition
CRecognitionResultHolder	Recognition result holder with methods to operate with the results
CSerializationProperties	The `SerializationProperties` class represents properties of serialization