Open source RDBMS designed to be a "drop-in" replacement for MySQL. Add a version-specific tag like mariadb-10.2 if that context is important.
MariaDB is a community-developed, open source (GPL v2 license) relational database management system. It aims to be a binary replacement for MySQL, but also provides new options, extension and storage engines.
For more information, including compatibility details, please see MariaDB versus MySQL - Compatibility