/usr/include/GNUstep/SaxObjC/ is in libsope-dev 2.2.17-1build2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/GNUstep/SaxObjC/SaxAttributeList.h
/usr/include/GNUstep/SaxObjC/SaxAttributes.h
/usr/include/GNUstep/SaxObjC/SaxContentHandler.h
/usr/include/GNUstep/SaxObjC/SaxDTDHandler.h
/usr/include/GNUstep/SaxObjC/SaxDeclHandler.h
/usr/include/GNUstep/SaxObjC/SaxDefaultHandler.h
/usr/include/GNUstep/SaxObjC/SaxDocumentHandler.h
/usr/include/GNUstep/SaxObjC/SaxEntityResolver.h
/usr/include/GNUstep/SaxObjC/SaxErrorHandler.h
/usr/include/GNUstep/SaxObjC/SaxException.h
/usr/include/GNUstep/SaxObjC/SaxHandlerBase.h
/usr/include/GNUstep/SaxObjC/SaxLexicalHandler.h
/usr/include/GNUstep/SaxObjC/SaxLocator.h
/usr/include/GNUstep/SaxObjC/SaxMethodCallHandler.h
/usr/include/GNUstep/SaxObjC/SaxNamespaceSupport.h
/usr/include/GNUstep/SaxObjC/SaxObjC.h
/usr/include/GNUstep/SaxObjC/SaxObjectDecoder.h
/usr/include/GNUstep/SaxObjC/SaxObjectModel.h
/usr/include/GNUstep/SaxObjC/SaxXMLFilter.h
/usr/include/GNUstep/SaxObjC/SaxXMLReader.h
/usr/include/GNUstep/SaxObjC/SaxXMLReaderFactory.h
/usr/include/GNUstep/SaxObjC/XMLNamespaces.h