/usr/include/sbml/xml/ is in libsbml5-dev 5.12.0+dfsg-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/sbml/xml/ExpatAttributes.h
/usr/include/sbml/xml/ExpatHandler.h
/usr/include/sbml/xml/ExpatParser.h
/usr/include/sbml/xml/LibXMLAttributes.h
/usr/include/sbml/xml/LibXMLHandler.h
/usr/include/sbml/xml/LibXMLNamespaces.h
/usr/include/sbml/xml/LibXMLParser.h
/usr/include/sbml/xml/LibXMLTranscode.h
/usr/include/sbml/xml/XMLAttributes.h
/usr/include/sbml/xml/XMLBuffer.h
/usr/include/sbml/xml/XMLConstructorException.h
/usr/include/sbml/xml/XMLError.h
/usr/include/sbml/xml/XMLErrorLog.h
/usr/include/sbml/xml/XMLExtern.h
/usr/include/sbml/xml/XMLFileBuffer.h
/usr/include/sbml/xml/XMLHandler.h
/usr/include/sbml/xml/XMLInputStream.h
/usr/include/sbml/xml/XMLLogOverride.h
/usr/include/sbml/xml/XMLMemoryBuffer.h
/usr/include/sbml/xml/XMLNamespaces.h
/usr/include/sbml/xml/XMLNode.h
/usr/include/sbml/xml/XMLOutputStream.h
/usr/include/sbml/xml/XMLParser.h
/usr/include/sbml/xml/XMLToken.h
/usr/include/sbml/xml/XMLTokenizer.h
/usr/include/sbml/xml/XMLTriple.h
/usr/include/sbml/xml/XercesAttributes.h
/usr/include/sbml/xml/XercesHandler.h
/usr/include/sbml/xml/XercesNamespaces.h
/usr/include/sbml/xml/XercesParser.h
/usr/include/sbml/xml/XercesTranscode.h