c3270 Lineage

Here is the official copyright notice for c3270 3.2:
Modifications Copyright © 1993, 1994, 1995, 1996, 1997, 1999, 2000 by Paul Mattes.
Original X11 Port Copyright © 1990 by Jeff Sparkes.
Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation.

Copyright © 1989 by Georgia Tech Research Corporation, Atlanta, GA 30332.
All Rights Reserved. GTRC hereby grants public use of this software. Derivative works based on this software must incorporate this copyright notice.

The 5250 emulation code carries one more copyright:
5250 Emulation Code Copyright © Minolta (Schweiz) AG, Beat Rubischon.
What this means is that you (whomever you may be) may use x3270 3.1 for whatever purpose you desire, and the only restriction is that you include the above notices in each copy or derivative work you distribute.

c3270 3.2 is a derivative of x3270 3.2, which comes from several sources:

                                   x3270 1.2
              |                       |                        |
              V                       V                        V
 x3270 1.2-cutpaste-iso8859-1     x3270 2.65               x3270 3.1
                                                           x3270 3.2
                                                            c3270 3.2
                                                         [you are here]
The original work was 3270tool, a 3270 emulator for Suntools (Sun's original proprietary windowing environment). This was developed by Robert Viduya at Georgia Tech, and is why GTRC's copyright notice is first.

3270tool was then ported to X11R4 by Jeff Sparkes, and given the name "x3270." This is why his name is second.

x3270 3.1 started with Jeff's x3270 version 1.2, and was made very much bigger by Paul Mattes, with contributions and suggestions by a number of users from the net.

x3270 then evolved into version 3.2, which is built much more modularly; a derivative of that version is this code, c3270.