Put the interesting parts of XZ Utils into the public domain.

Some minor documentation cleanups were made at the same time.

1 files changed, 51 insertions, 16 deletions

diff --git a/COPYING b/COPYING
index 0f4782a6..8f5a85ba 100644
--- a/COPYING
+++ b/COPYING
@@ -1,25 +1,60 @@
 
-LZMA Utils Licenses
--------------------
+XZ Utils Licensing
+==================
 
     Different licenses apply to different files in this package. Here
-    is a rough summary of which license apply to which parts of this
+    is a rough summary of which licenses apply to which parts of this
     package (but check the individual files to be sure!):
-      - Everything under src/liblzma/check and tests/files is public
-        domain.
-      - Everything else under the src directory is under the GNU LGPL
-        2.1 or (at your opinion) any later version.
-      - Outside the src directory, there are some files that are under
-        the GNU GPL 2 or (at your opinion) any later version, or under
-        the GNU GPL 3 or (at your opinion) any later version.
-      - Most documentation files are under an all-permissive license.
-
-    The following license texts are included in the following files
-    in this package:
+
+      - liblzma is in the public domain.
+
+      - xz, xzdec, and lzmadec command line tools are in the public
+        domain unless GNU getopt_long had to be compiled and linked
+        in from the lib directory. The getopt_long code is under
+        GNU LGPLv2.1+.
+
+      - The scripts to grep, diff, and view compressed files have been
+        adapted from gzip. These scripts and their documentation are
+        under GNU GPLv2+.
+
+      - All the documentation in the doc directory and most of the
+        XZ Utils specific documentation files in other directories
+        are in the public domain.
+
+      - Translated messages are in the public domain.
+
+      - The build system contains public domain files, and files that
+        are under GNU GPLv2+ or GNU GPLv3+. None of these files end up
+        in the binaries being built.
+
+      - Test files and test code in the tests directory, and debugging
+        utilities in the debug directory are in the public domain.
+
+      - The extra directory may contain public domain files, and files
+        that are under various free software licenses.
+
+    You can do whatever you want with the files that have been put into
+    the public domain. If you find public domain legally problematic,
+    take the previous sentence as a license grant. If you still find
+    the lack of copyright legally problematic, you have too many
+    lawyers.
+
+    If you copy significant amounts of public domain code from XZ Utils
+    into your project, acknowledging this somewhere in your software is
+    polite, but naturally it is not legally required.
+
+    As usual, this software is provided "as is", without any warranty.
+
+    The following license texts are included in the following files:
       - COPYING.LGPLv2.1: GNU Lesser General Public License version 2.1
       - COPYING.GPLv2: GNU General Public License version 2
       - COPYING.GPLv3: GNU General Public License version 3
 
-    If you have questions, don't hesitate to ask the copyright holder(s)
-    for more information.
+    Note that the toolchain (compiler, linker etc.) may add some code
+    pieces that are copyrighted. Thus, it is possible that e.g. liblzma
+    binary wouldn't actually be in the public domain in its entirety
+    even though it contains no copyrighted code from this package.
+
+    If you have questions, don't hesitate to ask the author(s) for more
+    information.