returns an empty string instead.
As a special case for the date-type fields, you may specify a format for
-the date by adding one of `:default`, `:relative`, `:short`, `:local`,
-`:iso8601`, `:rfc2822` or `:raw` to the end of the fieldname; e.g.
-`%(taggerdate:relative)`.
+the date by adding `:` followed by date format name (see the
+values the `--date` option to linkgit::git-rev-list[1] takes).
EXAMPLES