mariadb-backup is not considering O/S user when --user option is omitted

When the --user option in mariadb-backup is omitted mariadb-backup uses the anonymous user (''@localhost) instead of O/S user (root@localhost)

mariadb-backup --user=root --backup --target-dir=/tmp/backup
-> works as expected

mariadb-backup --backup --target-dir=/tmp/backup
231127 16:00:17 13772 Connect @localhost on using Socket
13772 Connect Access denied for user ''@'localhost' (using password: NO)

This does NEITHER reflect the general behaviour of all other MariaDB client utilities NOR does it match the documentation:

mariadb-backup --help
-u, --user=name This option specifies the MySQL username used when
connecting to the server, if that's not the current user.

Documentation states: https://mariadb.com/kb/en/mariabackup-options/#-user
" Defines the username for connecting to the MariaDB Server.
When Mariabackup runs it connects to the specified MariaDB Server to get its backups. Using this option, you can define the database user uses for authentication."

Further there is a type on in the docu: "database users uses" -> "database user used"

Do we have: a docu typo AND a little bug in the software and a discrepancy between the --help output AND the documentation...