In the last years, a number of Open-Source Systems (OSS) have created parallel foundations, as legal instruments to better articulate the structure, collaboration and financial model for the project. Some examples are Apache, Linux, Mozilla, Eclipse or Django foundations. Nevertheless, foundations largely differ in the kind of mission they have and the support they provide to their project/s. In this paper we study the role of foundations in open source software development. We analyze the nature of 89 software foundations and then focus on the 18 most relevant ones to study their openness and influence in the development practices taking place in the endorsed projects. Our results reveal the existence of a significant number of foundations with the sole purpose of promoting the importance of the free software movement and/or that limit themselves to core legal aspects but do not play any role in the day-to-day operations of the project (e.g., a few of them are just umbrella organizations for a large variety of projects). Therefore, while useful, foundations do not remove the need for specific projects to develop their own governance, contribution and development policies.