copyright: Note SIP compliance of license texts.

Yes, a metalicense.

1 files changed, 35 insertions, 0 deletions

diff --git a/copyright b/copyright
index e80a30a..f8324ee 100644
--- a/copyright
+++ b/copyright
@@ -80,6 +80,41 @@ Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.
 
+Permission to Modify GNU Licenses
+---------------------------------
+
+From <https://www.gnu.org/licenses/gpl-faq.html#ModifyGPL>:
+
+    *Can I modify the GPL and make a modified license?*
+
+      It is possible to make modified versions of the GPL, but it
+      tends to have practical consequences.
+
+      You can legally use the GPL terms (possibly modified) in another license
+      provided that you call your license by another name and do not include
+      the GPL preamble, and provided you modify the instructions-for-use at
+      the end enough to make it clearly different in wording and not mention
+      GNU (though the actual procedure you describe may be similar).
+
+      If you want to use our preamble in a modified license, please write
+      to <licensing@gnu.org> for permission.  For this purpose we would want
+      to check the actual license requirements to see if we approve of them.
+
+      Although we will not raise legal objections to your making a modified
+      license in this way, we hope you will think twice and not do it.  Such
+      a modified license is almost certainly incompatible with the GNU GPL,
+      and that incompatibility blocks useful combinations of modules.  The
+      mere proliferation of different free software licenses is a burden in
+      and of itself.
+
+      Rather than modifying the GPL, please use the exception mechanism
+      offered by GPL version 3.
+
+With the above permission, these licenses are themselves free software and
+comply with ProteanOS's Software Inclusion Policy.  However, these files
+describe the terms under which other packages may be used, so of course we do
+not and will not modify these files.
+
 
 Distribution Packaging
 ======================