/usr/include/ is in libxml++2.6-dev 2.36.0-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libxml++-2.6/
/usr/include/libxml++-2.6/libxml++/
/usr/include/libxml++-2.6/libxml++/validators/
/usr/include/libxml++-2.6/libxml++/validators/schemavalidator.h
/usr/include/libxml++-2.6/libxml++/validators/validator.h
/usr/include/libxml++-2.6/libxml++/validators/dtdvalidator.h
/usr/include/libxml++-2.6/libxml++/parsers/
/usr/include/libxml++-2.6/libxml++/parsers/textreader.h
/usr/include/libxml++-2.6/libxml++/parsers/parser.h
/usr/include/libxml++-2.6/libxml++/parsers/saxparser.h
/usr/include/libxml++-2.6/libxml++/parsers/domparser.h
/usr/include/libxml++-2.6/libxml++/nodes/
/usr/include/libxml++-2.6/libxml++/nodes/element.h
/usr/include/libxml++-2.6/libxml++/nodes/cdatanode.h
/usr/include/libxml++-2.6/libxml++/nodes/node.h
/usr/include/libxml++-2.6/libxml++/nodes/xincludestart.h
/usr/include/libxml++-2.6/libxml++/nodes/textnode.h
/usr/include/libxml++-2.6/libxml++/nodes/xincludeend.h
/usr/include/libxml++-2.6/libxml++/nodes/processinginstructionnode.h
/usr/include/libxml++-2.6/libxml++/nodes/commentnode.h
/usr/include/libxml++-2.6/libxml++/nodes/entityreference.h
/usr/include/libxml++-2.6/libxml++/nodes/entitydeclaration.h
/usr/include/libxml++-2.6/libxml++/nodes/contentnode.h
/usr/include/libxml++-2.6/libxml++/attributenode.h
/usr/include/libxml++-2.6/libxml++/attribute.h
/usr/include/libxml++-2.6/libxml++/document.h
/usr/include/libxml++-2.6/libxml++/dtd.h
/usr/include/libxml++-2.6/libxml++/libxml++.h
/usr/include/libxml++-2.6/libxml++/attributedeclaration.h
/usr/include/libxml++-2.6/libxml++/exceptions/
/usr/include/libxml++-2.6/libxml++/exceptions/parse_error.h
/usr/include/libxml++-2.6/libxml++/exceptions/validity_error.h
/usr/include/libxml++-2.6/libxml++/exceptions/exception.h
/usr/include/libxml++-2.6/libxml++/exceptions/internal_error.h
/usr/include/libxml++-2.6/libxml++/keepblanks.h
/usr/include/libxml++-2.6/libxml++/io/
/usr/include/libxml++-2.6/libxml++/io/ostreamoutputbuffer.h
/usr/include/libxml++-2.6/libxml++/io/outputbuffer.h
/usr/include/libxml++-2.6/libxml++/io/parserinputbuffer.h
/usr/include/libxml++-2.6/libxml++/io/istreamparserinputbuffer.h
/usr/include/libxml++-2.6/libxml++/noncopyable.h
/usr/include/libxml++-2.6/libxml++/schema.h