purpose of "/usr/lib/modules-load.d" & "/usr/lib/modprobe.d" ?

[Bruno Wolff III]

On Sat, Jul 21, 2012 at 16:15:51 +0200,
   Frantisek Hanzlik <franta at hanzlici.cz> wrote:
>
>are quite equivalent? When yes - we had there for long time
>"/etc/modprobe.conf" and "/etc/modprobe.d/", thus why are there another two
>directories?

The /usr/lib directories are for package installation. The /etc directories 
are for the admin. If the same named file is in both the /usr/lib and /etc 
directories only the /etc version is used.