xvfb-run is a linux utility that starts a virtual X-server. This is useful for performing rendering jobs on headless servers and cluster environments, as an easier alternative to X-11 forwarding with SSH. The XvfbRun enhancer wraps commands with this call. It’s safer than manually prepending xvfb-run -a to your command, automatically handling quote escaping and preventing typos. It also checks the $DISPLAY variable to see if xvfb-run is necessary, so it’s safe to use on any system.