/usr/include/sbml/conversion/ is in libsbml5-dev 5.10.0+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/sbml/conversion/ConversionOption.h
/usr/include/sbml/conversion/ConversionProperties.h
/usr/include/sbml/conversion/SBMLConverter.h
/usr/include/sbml/conversion/SBMLConverterRegister.h
/usr/include/sbml/conversion/SBMLConverterRegistry.h
/usr/include/sbml/conversion/SBMLFunctionDefinitionConverter.h
/usr/include/sbml/conversion/SBMLIdConverter.h
/usr/include/sbml/conversion/SBMLInferUnitsConverter.h
/usr/include/sbml/conversion/SBMLInitialAssignmentConverter.h
/usr/include/sbml/conversion/SBMLLevelVersionConverter.h
/usr/include/sbml/conversion/SBMLLocalParameterConverter.h
/usr/include/sbml/conversion/SBMLReactionConverter.h
/usr/include/sbml/conversion/SBMLRuleConverter.h
/usr/include/sbml/conversion/SBMLStripPackageConverter.h
/usr/include/sbml/conversion/SBMLUnitsConverter.h