The copyright of the Real Player installer for Debian is GPL, version 2.

The postinst of this package contains code derived from rpm2cpio
(http://www.eleves.ens.fr:8080/home/espel/rpm2cpio), with the following
copyright:

# Copyright (C) 1997,1998,1999, Roger Espel Llima
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and any associated documentation files (the "Software"), to 
# deal in the Software without restriction, including without limitation the 
# rights to use, copy, modify, merge, publish, distribute, sublicense, 
# and/or sell copies of the Software, and to permit persons to whom the 
# Software is furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# SOFTWARE'S COPYRIGHT HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE

The copyright of the Real Player itself is explained in the LICENSE
file and does not apply to this installer package. Read it before deciding
to use Real Player -- it's quite nasty.