[root@localhost ~]# cd /etc/X11/xorg.conf.d/
You have new mail in /var/spool/mail/root
[root@localhost xorg.conf.d]# ls
00-system-setup-keyboard.conf  50-vboxmouse.conf
[root@localhost xorg.conf.d]# cat *
# This file is autogenerated by system-setup-keyboard. Any
# modifications will be lost.

Section "InputClass"
    Identifier  "system-setup-keyboard"
    MatchIsKeyboard "on"
    Option      "XkbModel"  "pc105+inet"
    Option      "XkbLayout" "us"
#   Option      "XkbVariant"    "(null)"
    Option      "XkbOptions"    "terminate:ctrl_alt_bksp,"
EndSection
Section "InputClass"
    Identifier  "vboxmouse"
    MatchDevicePath "/dev/vboxguest"
    Driver      "vboxmouse"
EndSection
[root@localhost xorg.conf.d]#