+ **sender**
+ Output all addresses from the *From* header that appear on
+ any message matching the search terms, either one per line
+ (--format=text), separated by null characters
+ (--format=text0), as a JSON array (--format=json), or as
+ an S-Expression list (--format=sexp).
+
+ Note: Searching for **sender** should be much faster than
+ searching for **recipients**, because sender addresses are
+ cached directly in the database whereas other addresses
+ need to be fetched from message files.
+
+ **recipients**
+ Like **sender** but for addresses from *To*, *Cc* and
+ *Bcc* headers.
+
+ This option can be given multiple times to combine different
+ outputs. Currently, this is only supported for **sender** and
+ **recipients** outputs.
+