This package contains the initialization for the PostgreSQL database system. If this initialization is installed, the user "postgres" is able to setup additional database users; cf. the documentation under /usr/doc/packages/postgres/html/index.html.
Please, check the configuration file /var/lib/pgsql/data/pg_hba.conf; the manual page pg_hba.conf(5) explains the background!
Please, install this package only during the first installation or while doing a PostgreSQL "major number update"! If a database already exists, it will be saved unter /var/lib/pgsql/data.old; please, remove the directory /var/lib/pgsql/data.old, if you do not need it anymore.
Only delete this package, if you do not want to use the PostgreSQL database system anymore!