Quoting Martin Michlmayr <tbm@cyrius.com>:
Package: xf86cfgI cannot find such a package or tool, even though it seems X.org includes one.
I did have the same problem as you: I did not know where does the file comes from: quijote:/# which xf86cfg /usr/bin/X11/xf86cfg quijote:/# dpkg -S /usr/bin/X11/xf86cfg dpkg: /usr/bin/X11/xf86cfg not found. However: quijote:/# dpkg -L xbase-clients | grep 86 /etc/X11/app-defaults/XF86Cfg /usr/X11R6/bin/xf86cfg /usr/X11R6/bin/xf86config /usr/X11R6/man/man1/xf86cfg.1x.gz /usr/X11R6/man/man1/xf86config.1x.gz this was because of a link: quijote:/# ls -ld /usr/bin/X11 lrwxrwxrwx 1 root root 12 Aug 10 12:53 /usr/bin/X11 -> ../X11R6/bin