MySQL Workbench is a cross-platform, visual database design
tool developed by MySQL.  It is the highly anticipated successor
application of the DBDesigner4 project.  MySQL Workbench is available
as a native GUI tool on Windows, Linux, and OS X in different
editions.

MySQL Workbench provides DBAs and developers an integrated tools
environment for:
* Database Design & Modeling
* SQL Development (replacing MySQL Query Browser)
* Database Administration (replacing MySQL Administrator)

You need to allow MySQL to accept incoming connections from outside:
For Slackware 15.0, this option is in /etc/rc.d/rc.mysqld.
Remove or comment this line:  SKIP="--skip-networking"  and then do:
/etc/rc.d/rc.mysqld restart

NOTE: For current, this option is moved to /etc/default/mariadb
Remove --skip-networking from MARIADB_OPTIONS line

Note: MySQL Workbench will be built against Python 2.7 even when
Python 3.x is installed on your system

NOTE: You may need to run mysql_upgrade if mysql-workbench could not
fetch your metadata. You may need to add this into /etc/ld.so.conf:
/usr/lib{64}/mysql-workbench

NOTE: This script requires a lot of RAM in order to build. If you have
small amount of memory, please consider adding zram.

The last version working with MariaDB is 8.0.47
Version 26.x and beyond no longer works with MariaDB