Change: write a licensing page

1 files changed, 40 insertions, 2 deletions

diff --git a/license.mdwn b/license.mdwn
index 06b6b35..e93c07b 100644
--- a/license.mdwn
+++ b/license.mdwn
@@ -1,3 +1,41 @@
-[[!meta title="License for XXX and this website"]]
+[[!meta title="Licenses"]]
 
-FIXME: This needs to be written.
+[four freedoms]: https://www.gnu.org/philosophy/free-sw.html
+[GNU General Public Licence, version 3 or later]: https://www.gnu.org/licenses/gpl-3.0.html
+[Apache 2.0]: https://www.apache.org/licenses/LICENSE-2.0
+[CC-BY-SA 4.0 (International)]: https://creativecommons.org/licenses/by-sa/4.0/
+
+We have chosen software licenses for this project following these
+principles:
+
+* XXX itself is free software, meaning it provides all the [four
+  freedoms][] as defined by the Free Software Foundation: use (for
+  whatever purpose), study and change, share, share modified versions.
+
+* XXX should have little effect on the licensing of the outputs.
+
+While we would prefer it if everyone only produced free software, we
+don't want to mandate it, and thus we've chosen to use a mix of
+permissive and copyleft licenses for different parts of the project.
+
+As long as you only run XXX, you don't need to care about the
+licences, and you can use the outputs as you wish.
+
+* The XXX tooling (document and test program generators) are
+  licensed under the [GNU General Public Licence, version 3 or
+  later][].
+
+* The documents and test programs generated by XXX have whatever
+  licence the input documents have. XXX has no effect on their
+  licences.
+
+* XXX uses templates, libraries, and scaffolding to produce the test
+  programs. These are licensed under the [Apache 2.0][] licence, but
+  with the extra permission that when they're used to generate outputs
+  by XXX, they don't affect the licence of the generated test
+  programs. The programs generated by XXX have the license of the
+  inputs.
+
+* The XXX documentation, inluding examples, are licensed under the
+  [CC-BY-SA 4.0 (International)][] licence. This is better suited for
+  documentation than the code licences above.