/usr/share/postgresql/10/ is in postgresql-plperl-10 10.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/postgresql/10/extension/
/usr/share/postgresql/10/extension/hstore_plperl--1.0.sql
/usr/share/postgresql/10/extension/hstore_plperl.control
/usr/share/postgresql/10/extension/hstore_plperlu--1.0.sql
/usr/share/postgresql/10/extension/hstore_plperlu.control
/usr/share/postgresql/10/extension/plperl--1.0.sql
/usr/share/postgresql/10/extension/plperl--unpackaged--1.0.sql
/usr/share/postgresql/10/extension/plperl.control
/usr/share/postgresql/10/extension/plperlu--1.0.sql
/usr/share/postgresql/10/extension/plperlu--unpackaged--1.0.sql
/usr/share/postgresql/10/extension/plperlu.control