docs: Make room for format version in doc of bundle metadata

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

diff --git a/docs/bundles.rst b/docs/bundles.rst
index 42ce49e939bb6d04f0234ee21d16a231a7716825..5ae6517626d1da8be5cda30135d61f7d33913d0c 100644 (file)
--- a/docs/bundles.rst
+++ b/docs/bundles.rst
@@ -70,9 +70,13 @@ must refer to it in lowercase.
 ``otter.toml`` bundle top-level metadata
 ----------------------------------------
 
-The top-level ``otter.toml`` contains a single entry ``title``, which
-should be a string.  This is useful because the zipfile's name is not
-stored in the server.
+The top-level ``otter.toml`` contains the following keys:
+
+ * ``title`` identifying the bundle.  This is useful because the
+   zipfile's name is not stored in the server.
+   [string, mandatory]
+
+Newer versions of Otter may assign meanings to other keys.
 
 Bundle management
 -----------------