/usr/include/postgresql/10/server/common/ is in postgresql-server-dev-10 10.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/postgresql/10/server/common/base64.h
/usr/include/postgresql/10/server/common/config_info.h
/usr/include/postgresql/10/server/common/controldata_utils.h
/usr/include/postgresql/10/server/common/fe_memutils.h
/usr/include/postgresql/10/server/common/file_utils.h
/usr/include/postgresql/10/server/common/int128.h
/usr/include/postgresql/10/server/common/ip.h
/usr/include/postgresql/10/server/common/keywords.h
/usr/include/postgresql/10/server/common/md5.h
/usr/include/postgresql/10/server/common/pg_lzcompress.h
/usr/include/postgresql/10/server/common/relpath.h
/usr/include/postgresql/10/server/common/restricted_token.h
/usr/include/postgresql/10/server/common/saslprep.h
/usr/include/postgresql/10/server/common/scram-common.h
/usr/include/postgresql/10/server/common/sha2.h
/usr/include/postgresql/10/server/common/string.h
/usr/include/postgresql/10/server/common/unicode_norm.h
/usr/include/postgresql/10/server/common/unicode_norm_table.h
/usr/include/postgresql/10/server/common/username.h