X11Libre is a collection of packages forked from Xorg. However, most of the forks are not any more updated than the official Xorg packages. The main one that gets active development is the xserver. There are no promises of a stable ABI and does not have a stable release. The project has had several changes that are controversial. As such, it is largely up to the user if they want to use the software from the project. It has broken some things but can lead to a smoother experience.
This section will only cover the installation and configuration of the xserver. It will also cover on how to proceed. It will not cover its history, why the fork took place, or the nature of the person who forked Xorg. This book only aims to guide users for installing what they need and what pieces are needed to be put in place. Lastly, please do not ask for this project to be put in BLFS/GLFS. The future for this project is very unclear and may die out before SLFS-12.4 releases in September. Consider this a reference implementation rather than the future.