Comment 14 for bug 546933

If you mean that the video driver autoconfig works differently when there's an xorg.conf, then the autoconfig/fallback patch from SUSE fixes that. And if there's a Driver section in xorg.conf, the autoconfig path is bypassed (like before).

I'm not aware of (or can't remember) other differences having a minimal xorg.conf or none at all.

<edit>

yes it's included, that's the whole point of this being accepted in debian :) (because it's sort of a failsafe mode to fall back on vesa/fbdev if the primary driver doesn't work)