/var/postgresql/data/postgresql.conf : This file is read by psql on server startup.
/var/postgresql/data/postgresql.auto.conf : This is also read at server startup. Should not be edited manually. Config options are set with ALTER SYSTEM command.
/var/postgresql/data/pg_hba.conf: Contains : psql user account information.
/var/postgresql/data/pg_ident.conf : Contains mapping from psql user accounts to system accounts.
We probably don't need last two files. Better to recreate them when restoring the database.
Backup script: /root/scripts/psql_cfg_rsync_backup.plx