+
--
1. If the starting point is specified as `ref@{Nth}`, show the index
-format.
+ format.
+
2. If the starting point was specified as `ref@{now}`, show the
-timestamp format.
+ timestamp format.
+
3. If neither was used, but `--date` was given on the command line, show
-the timestamp in the format requested by `--date`.
+ the timestamp in the format requested by `--date`.
+
4. Otherwise, show the index format.
--