Upon upgrade from MySQL to MariaDB master-info-repository and relay-log-info-repository are completely ignored without even warning in .err log. This causes troubles when migrating slave servers. There should be at least warning if not error in .err log.
Ideally mysql_upgrade script should take care of that and extract the data from mysql.slave_master_info and mysql.slave_relay_log_info to store them in master.info file.
I'd like to see MariaDB support table-based master info repository (see https://dev.mysql.com/doc/refman/5.6/en/replication-options-slave.html#option_mysqld_master-info-repository). If an InnoDB table were used, it could be encrypted. This would be preferable to having to put the password in plaintext in a text file.