slackbuilds/system/xvfb-run

xvfb-run (run a command in a virtual X server environment)

xvfb-run is a script using the virtual framebufer X server (xvfb)
to run X programs from command line. Note that xvfb doesn't actually
display anything; you won't be able to see or interact with the X
application.

This can be useful for software that expects to connect to an X server
as part of its build process.