The XFA specification is referenced from ISO 32000-1/PDF 1.7 as an external proprietary specification, and was entirely deprecated from PDF with ISO 32000-2 (PDF 2.0).
The XFA specification was not included in ISO 32000-1/PDF 1.7 and is only referenced as an external proprietary specification created by Adobe. XFA is deprecated in ISO 32000-2 (PDF 2.0).