`--date=rfc` (or `--date=rfc2822`) shows timestamps in RFC 2822
format, often found in E-mail messages.
+
-`--date=short` shows only date but not time, in `YYYY-MM-DD` fomat.
+`--date=short` shows only date but not time, in `YYYY-MM-DD` format.
+
`--date=default` shows timestamps in the original timezone
(either committer's or author's).