1. XFree86 version of Mesa 3D graphics library Mesa is a 3D graphics library which presents an API intended to be compatible with OpenGL. XFree86 maintains its own version of the Mesa library (which is regularly resynchronized with the official one) to permit development of the XFree86 X server's Direct Rendering Infrastructure (DRI), which makes the 3D acceleration features of many modern video cards available to X client programmers. Chipset-specific DRI modules, if available for your machine architecture, are provided in this package. (Unlike the modules in the xserver-xfree86 package, the DRI modules are loaded by the Mesa library, not by the X server itself.) From Debian 3.0r0 APT