Knit is "free software," also known as "open source software."
The basic license is so-called "BSD-style", which means that except for
retaining the copyright and permission/disclaimer notices, there is
essentially no restriction on use, modification, or redistribution.

Each file contains its license(s); the following is a summary.

1. The Knit compiler and tools are covered by a license similar to
so-called "BSD" or "MIT"-style licenses, although with slightly fewer
constraints:

   Copyright (c) 2000, 2001 University of Utah and the Flux Group.
   
   This file is part of the Knit component composition software.
   
   Permission to use, copy, modify, distribute, and sell this software and
   its documentation is hereby granted without fee, provided that the above
   copyright notice and this permission/disclaimer notice is retained in all
   copies or modified versions, and that both notices appear in supporting
   documentation.  THE COPYRIGHT HOLDERS PROVIDE THIS SOFTWARE "AS IS" AND
   WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION,
   THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   PURPOSE.  THE COPYRIGHT HOLDERS DISCLAIM ANY LIABILITY OF ANY KIND FOR
   ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   
   Users are requested, but not required, to send to csl-dist@cs.utah.edu any
   improvements that they make and grant Univ. of Utah redistribution rights.


2. The example programs are entirely without constraint:

   Copyright (c) 2000 University of Utah and the Flux Group.
   
   Permission to use, copy, modify, and distribute this file
   for any purpose with or without restriction is hereby granted.


3. Documentation is covered by this license:

  Copyright (c) 2000, 2001 University of Utah and the Flux Group.
  
  Permission is granted to make and distribute verbatim copies of this
  document provided the copyright notice and this permission notice are
  preserved on all copies.  Modified versions of this document may be
  copied and distributed with the additional condition that the entire
  resulting derived work is distributed under the terms of a permission
  notice identical to this one.