Xenocara is the OpenBSD build infrastructure for the project's customised X.Org Server that utilises a dedicated _x11 user by default to drop privileges and perform privilege separation in accordance to OpenBSD's "least privilege" policy. The patches for applying this rather important security protection were provided to upstream for the benefit of other Unix-like systems such as Linux, however the care to apply and maintain them has unfortunately not happened to date.
Until release 6.9, X.Org used imake but recent modularised versions have switched to GNUautotools. Xenocara uses BSDmake and is designed to ease building and maintenance of modularised X.Org within the OpenBSD CVS tree. It first appeared with OpenBSD 4.2, released on 1 November 2007.