SlackBuildsOrg/desktop/lumina

The Lumina Desktop Environment (Lumina for short) is a lightweight,
XDG-compliant, BSD-licensed desktop environment that focuses specifically
on streamlining the ability to get work done while minimizing system
overhead.

It is specifically designed for PC-BSD(r) and FreeBSD, but has also
been ported to many other BSD and Linux operating systems. It is based
on the Qt graphical toolkit and the Fluxbox window manager, and uses
a small number of X utilities for various tasks, such as numlockx and
xscreensaver.

"acpi" is an optional dependency for the battery monitor.