[winswitch] Does installing Xpra require installing an X server?

[Stephen Fromm]

I'm looking for an alternative to installing X on a remote server and then
using VNC+ssh tunnelling.

When I followed instructions for installing on CentOS via RPM, it pulled in
an X11 server as a dependency:
    Package xorg-x11-server-Xorg.x86_64 0:1.15.0-36.el6.centos will be
installed

Do I need to install an X server to run xpra?

TIA,

S