grub.conf is a Red hat creation, its not used by grub. In Redhat grub.conf is a symlink to the file /boot/grub/menu.lst ( or it maybe the other way around ). Don't know why they did this, but it confused the hell out of me for a while as well
/boot/grub/menu.lst is where you'll find what your looking for. Read the grub manual for more details. and also read the notes left by the debian team they've added bits so it can be automatically created when you add your own kernels.
Where is grub.conf in Debian?
