copyright: notice re formalities

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/debian/copyright b/debian/copyright
index 9567297f76518351c4a04d6990a2c1be04d6fb4c..c483ced40cb4008e7c2ec1299a8727d88298d5a3 100644 (file)
--- a/debian/copyright
+++ b/debian/copyright
@@ -22,3 +22,22 @@ The client and server are:
 
 On a Debian system, the GNU General Public License v3 can be found in
 /usr/share/common-licenses/GPL-3
+
+
+Formalities
+-----------
+
+The licence is generally indicated in each file with an SPDX
+delcaration; as is conventional, this should be read as a licence
+grant.
+
+Contributions to Hippotat are accepted based on the git commit
+Signed-off-by convention, by which the contributors' certify their
+contributions according to the Developer Certificate of Origin version
+1.1 - see the file DEVELOPER-CERTIFICATE.
+
+If you create a new file please be sure to add an appropriate licence
+header, probably something like this:
+// Copyright 2017-2022 Ian Jackson and contributors to Hippotat
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// There is NO WARRANTY.