The new MariaDB 10.0 do no longer require users to set a root password. This is a security feature. You don't need root passwords (or debian-maint-user passwords) simply to run and maintain your database anymore. If you have root on the system you will get in as root to the database (or using sudo).
For use cases where you need to access the database as some user from somewhere, just create a user and grant it the required permissions, and then use that user in your apps and other places. There is no need to have a general MySQL/MariaDB root user.
The new MariaDB 10.0 do no longer require users to set a root password. This is a security feature. You don't need root passwords (or debian-maint-user passwords) simply to run and maintain your database anymore. If you have root on the system you will get in as root to the database (or using sudo).
For use cases where you need to access the database as some user from somewhere, just create a user and grant it the required permissions, and then use that user in your apps and other places. There is no need to have a general MySQL/MariaDB root user.