MAME is a popular arcade gaming machine emulator that has been around for more than 19 years. The project’s original license prohibited commercial use and the project leaders determined this was hurting the software’s adoption. They decided to make the code free and open source in an effort to expand MAME’s usage and adoption.
The developer community has spent the last 10 months contacting all developers that have contributed to the project to get feedback on what license the community should use going forward. As a result of this effort, more than 90% of the code is now licensed under the 3-Clause BSD license, and the project as a whole is distributed under the GPLv2.0+.