/usr/include/postgresql/10/server/nodes/ is in postgresql-server-dev-10 10.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/postgresql/10/server/nodes/bitmapset.h
/usr/include/postgresql/10/server/nodes/execnodes.h
/usr/include/postgresql/10/server/nodes/extensible.h
/usr/include/postgresql/10/server/nodes/lockoptions.h
/usr/include/postgresql/10/server/nodes/makefuncs.h
/usr/include/postgresql/10/server/nodes/memnodes.h
/usr/include/postgresql/10/server/nodes/nodeFuncs.h
/usr/include/postgresql/10/server/nodes/nodes.h
/usr/include/postgresql/10/server/nodes/params.h
/usr/include/postgresql/10/server/nodes/parsenodes.h
/usr/include/postgresql/10/server/nodes/pg_list.h
/usr/include/postgresql/10/server/nodes/plannodes.h
/usr/include/postgresql/10/server/nodes/primnodes.h
/usr/include/postgresql/10/server/nodes/print.h
/usr/include/postgresql/10/server/nodes/readfuncs.h
/usr/include/postgresql/10/server/nodes/relation.h
/usr/include/postgresql/10/server/nodes/replnodes.h
/usr/include/postgresql/10/server/nodes/tidbitmap.h
/usr/include/postgresql/10/server/nodes/value.h