File 99-debug.conf of Package dracut.28355
# Below adds additional tools to the initrd which are not urgently necessary to
# bring up the system, but help to debug problems.
# See /usr/lib/dracut/modules.d/95debug/module-setup.sh which additional tools
# are installed and add more if you need them. This specifically helps if you
# use:
# rd.break=[cmdline|pre-udev|pre-trigger|initqueue|pre-mount|
# mount|pre-pivot|cleanup]
# boot parameter or if you are forced to enter the dracut emergency shell.
# add_dracutmodules+=debug