Thanks for the update linuxs.
In its present state, MariaDB 10.x, at least with regard to User Management, is not usable. And since User Management is a fundamental component, MariaDB 10.x is useless.
Also, I tried deleting some of the garbage users that appear in the User accounts overview page and I could not do it, instead I got an SQL error. The garbage users bug appears to be a PMA problem since I only saw the real users in HeidiSQL User management.