presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/glue/GlueHiveMetastore.java/GlueHiveMetastore/listRoles
class GlueHiveMetastore:    @Override
    public Set<String> listRoles()
    {
        return ImmutableSet.of(PUBLIC_ROLE_NAME);
    }