FOSS (Free and Open-Source Software) is a type of software that is available to the public for free and can be modified and redistributed by anyone. FOSS is typically developed collaboratively by a community of developers, and the source code is made available to the public. This allows anyone to modify the software and redistribute it, as long as they follow the terms of the license.

In the context of Drupal, FOSS is the foundation of the CMS. Drupal is an open-source content management system (CMS) that is released under the GNU General Public License (GPL). This means that anyone can download, modify, and redistribute the software, as long as they follow the terms of the license. This allows developers to customize the software to meet their specific needs, and it also allows for a vibrant community of developers to collaborate on the project.

FOSS is an important part of the Drupal community, as it allows developers to collaborate on the project and create innovative solutions. It also allows users to customize the software to meet their specific needs, and it encourages the development of new features and improvements. FOSS is an important part of the Drupal ecosystem, and it is essential for the continued success of the CMS.