Traditionally, the xorg.conf file is used to configure the X server. In Fedora,
the X configuration is determined automatically each time X is started. As a
result, no xorg.conf file is created. In most cases, this works well and there
is no need to manually specify X configuration.

If you need to make manual changes to your X configuration for any reason,
you will first need to create an xorg.conf file.
