/usr/include/libwnck-3.0/libwnck/ is in libwnck-3-dev 3.14.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libwnck-3.0/libwnck/application.h
/usr/include/libwnck-3.0/libwnck/class-group.h
/usr/include/libwnck-3.0/libwnck/libwnck.h
/usr/include/libwnck-3.0/libwnck/pager.h
/usr/include/libwnck-3.0/libwnck/screen.h
/usr/include/libwnck-3.0/libwnck/selector.h
/usr/include/libwnck-3.0/libwnck/tasklist.h
/usr/include/libwnck-3.0/libwnck/util.h
/usr/include/libwnck-3.0/libwnck/version.h
/usr/include/libwnck-3.0/libwnck/window-action-menu.h
/usr/include/libwnck-3.0/libwnck/window.h
/usr/include/libwnck-3.0/libwnck/wnck-enum-types.h
/usr/include/libwnck-3.0/libwnck/workspace.h