Complex sentence: HeidiSQL, previously known as MySQL-Front, is a free and open source client, or frontend for MySQL, its forks like MariaDB and Percona Server, Microsoft SQL Server and PostgreSQL, developed by German programmer Ansgar Becker and a few other contributors in Delphi.
Split into simpler sentences: HeidiSQL, previously known as MySQL-Front, is a free and open source client, or frontend for MySQL (and its forks like MariaDB and Percona Server, Microsoft SQL Server and PostgreSQL). HeidiSQL is developed by German programmer Ansgar Becker and a few other contributors in Delphi.