What is the story with XFree86s license?
The “wait-and-see” approach adopted by most vendors in the wake of Xouvert and freedesktop.org forks changed in January 2004, when the XFree86 project announced its intention to change the license on its codebase. The license, called the “XFree86 1.1 license”, combined elements of the traditional MIT/X11 license, the original 4-clause BSD license (containing the infamous “advertising clause”), and the Apache Software License in a novel way. The new license was found to be GPL-incompatible by Richard Stallman of the Free Software Foundation and most OS distributors, including Debian, whereas the XFree86 project makes contradictory and confusing claims.