PLT software is distributed under the GNU Library General Public License (LGPL). This means you can link PLT software (such as MzScheme or MrEd) into proprietary applications, provided you follow the specific rules stated in the LGPL. You can also modify PLT software; if you distribute a modified version, you must distribute it under the terms of the LGPL, which in particular means that you must release the source code for the modified software. See for more information.

PLT software includes or extends the following copyrighted material:

• DrScheme
  Copyright (c) 1995-2000 PLT
  All rights reserved.

• MrEd
  Copyright (c) 1995-2000 PLT (Matthew Flatt, Robert Bruce Findler, and John Clements)
  All rights reserved.

• MzScheme
  Copyright (c) 1995-2000 PLT (Matthew Flatt)
  All rights reserved.

• McMicMac
  Copyright (c) 1995-1998 PLT (Shriram Krishnamurthi) All rights reserved.

• libscheme
  Copyright (c) 1994 Brent Benson
  All rights reserved.

• wxWindows
  Copyright (c) 1994 Artificial Intelligence Applications Institute, The University of Edinburgh
  All rights reserved.

• wxWindows Xt
  Copyright (c) 1994 Artificial Intelligence Applications Institute, The University of Edinburgh
  Copyright (c) 1995 GNU (Markus Holzem)
  All rights reserved.

• Conservative garbage collector
  Copyright (c) 1988, 1989 Hans-J. Boehm, Alan J. Demers
  Copyright (c) 1991-1996 Xerox Corporation
  Copyright (c) 1996-1998 Silicon Graphics
  All rights reserved.

• Collector C++ extension by Jesse Hull and John Ellis
  Copyright (c) 1994 Xerox Corporation
  All rights reserved.

• The A List
  Copyright (c) 1997-2000 Kyle Hammond.
  All rights reserved.

• Independent JPEG Group library
  Copyright (c) 1991-1998, Thomas G. Lane.
  All rights reserved.