- rfc822-header-ref header-list field-name &optional defaultprocedure
An utility procedure to get a specific field from the parsed header list, which is returned by rfc822-header->list.
Field-name specifies the field name in a lowercase string. If the field with given name is in header-list, the procedure returns its value in a string. Otherwise, if default is given, it is returned, and if not, #f is returned.