Volition Copyright (applies to original FreeSpace2 source code developed and released by Volition):
Copyright (C) Volition, Inc. 1999. All rights reserved.
All source code herein is the property of Volition, Inc. You may not sell or otherwise commercially exploit the source or things you created based on the source.
Modifications by members of the FreeSpace Source Code Project are released under whatever terms the individual authors choose, but the above notice continues to apply to all fs2_open code.
All modifications made on or after November 1, 2020, shall be released under the terms within Unlicense. Modifications made before said date are released under the previous terms with the exception of modifications made by members of the FreeSpace Source Code Project that opt-in to the terms of Unlicense. Additionally, a list of contributors who have opted in to the Unlicense terms can be found in Licensing.
See Licensing for more information.