Xvfb; X virtual framebuffer, is an X11 server that can run graphic applications without a physical screen.
Xvfb is an X11 server that executes all the graphical operations in memory without showing any screen output.
It acts exactly like any other X widow server but with the difference that no output is shown so Xvfb does not require the computer it is running on to a screen.
It can be used for many things like remote controlling browsers in web testing, or background tasks running for creating screenshots of programs or web pages.
