I created database using mysql from phpmyadmin for some practice purposes. Now I've just downloaded and set up mysql workbench and right after I saw my old database which I created in phpmyadmin and that makes me wonder how did workbench get it?
Both phpMyAdmin and MySQL Workbench are administration/client tools. It is used to connect MySQL Service running on your machine / remote machine called server. (usually on port 3306).
When you create databases or store data which is stored under a folder represented as datadir which is owned by the MySQL service.
how did workbench get it?
Database is managed by MySQL Service, like a phpMyAdmin, Workbench also another client, connecting to same MySQL Service.
Similarly, you can use any other MySQL Client to connect with the same MySQL service running on your machine.
Additionally, you can refer my blog to understand more about MySQL Architecture.