THPDFHeadlessFormDataValueKind

THPDFHeadlessFormDataValueKind = (hfvAbsent, hfvText, hfvName, hfvArray);

Value	Payload
hfvAbsent	Name-only entry with no field mutation
hfvText	Exactly one Unicode Values element
hfvName	One decoded PDF byte name in NameValue
hfvArray	A Unicode Values array, including an empty array

FDF preserves these PDF value categories; XFDF maps byte names to scalar UTF-8 text and represents arrays as repeated value elements