I can't say how but the udev rules is assigning those devicenames. In the past, with the Kubuntu: http://kubuntuforums.net/forums/index.php?topic=3107885.0.
A readme: /etc/udev/rules.d/README
The files in this directory are read by udev(7) and used when events
are performed by the kernel. The udev daemon watches this directory
with inotify so that changes to these files are automatically picked
up, for this reason they must be files and not symlinks to another
location as in the case in Debian.
Packages do not generally install rules here, this directory is for
local rules. If you want to override behaviour of package-supplied
rules, which can be found in /lib/udev/rules.d, you can do one of two
1) Write your own rules in this directory that assign the name,
symlinks, permissions, etc. that you want. Pick a number higher
than the rules you want to override, and yours will be used.
2) Copy the file from /lib/udev/rules.d and edit it here; you
should generally only do this if you want to prevent a program
from being run.
If the ordering of files in this directory are not important to you,
it's recommended that you simply name your files
"descriptive-name.rules" such that they are processed AFTER all
numbered rules in both this directory and /lib/udev/rules.d and thus
override anything set there.
The /etc/udev/rules.d/70-persistent-cd.rules has the CD and the DVD rules. You could modify it:
This file was automatically generated by the /lib/udev/write_cd_rules
program, run by the cd-aliases-generator.rules rules file.
You can modify it, as long as you keep each rule on a single
line, and set the $GENERATED variable.