We believe that all of the code in this release (4.4.0) of XFree86 meet the requirements of the Open Source Definition, as maintained by the Open Source Initiative (OSI).
We believe that most of the code in this release (4.4.0) of XFree86 meets the requirements of the Free Software definition as defined by the Free Software Foundation (FSF).
The exceptions are the GLX extension and CID font code that are covered by the SGI Free Software License B, version 1.1.
The client-side X libraries distributed with this release (4.4.0), with the exception of the GL, GLU, and GLw libraries, carry a subset of the acceptable licenses that satisfy an additional condition: they are GPL-compatible. The GL, GLU, and GLw libraries contain code covered by the SGI Free Software License B, version 1.1, which is not GPL-compatible.
Other portions of XFree86, including the X servers, may include code with licenses that are not GPL-compatible. Example of such licenses include some of the BSD-style licenses, the FreeType License, the SGI licenses and the XFree86 License version 1.1.