Debian ships sources for unace, while we install precompiled files. The sources, along with a set of patches, can be found here:
The origin of the sources is explained in the copyright file:
The original source code was obtained by mail from the upstream author
Marcel Lemke <email@example.com>.
Copyright Holder: Ace Compression Software <firstname.lastname@example.org>
Copyright (C) 2005 Ace Compression Software <email@example.com>
All rights reserved.
Public UnAce Licence
The Public UnAce Package (v2.0 or later if not otherwise stated) is
distritbuted under the following licence:
"Package" refers to the collection of files distributed by the Copyright
Holder, and derivatives of that collection of files created through
"Standard Version" refers to such a Package if it has not been modified,
or has been modified in accordance with the wishes of the Copyright
"Distribution" as it is used here means making data available to a third
party. No matter in which way the data is made available.
"Copyright Holder" is ACE Compression Software.
"Distribution Partner" is e-merge GmbH (authorised signatory).
1. The Standard Version of Public UnAce Package may be freely
2. The UnAce sources may be used in any software to handle ACE archives
without limitations free of charge, but must not be used to reproduce
the ACE compression algorithm. This means that that the code must not
be used to develop an ACE compatible archiver (that is: software
capable of compressing to Ace archives) in any way.
3. Distribution of modified Public UnAce sources (as part of other
software or as stand-alone package) requires that it is clearly
stated in the documentation and source code that it is distributed
under the Public UnAce Licence. The Public UnAce Licence has to be
included in this package.
4. The name of the Copyright Holder or the support of ACE archives may
not be used to endorse or promote products derived from this package
without specific prior written permission from the Copyright Holder
or its Distribution Partner.
5. This Software is distributed "AS IS". NO WARRANTY OF ANY KIND IS
EXPRESSED OR IMPLIED. YOU USE AT YOUR OWN RISK. THE AUTHOR WILL NOT
BE LIABLE FOR DATA LOSS, DAMAGES, LOSS OF PROFITS OR ANY OTHER KIND
OF LOSS WHILE USING OR MISUSING THIS SOFTWARE.
6. Installing and using the Public UnAce Package signifies acceptance of
these terms and conditions of the license.
Marcel Lemke, ACE Compression Software
2.5-r1 in the tree with Debian's patchset