Default: "-- Mutt: Compose [Approx. msg size: %l Atts: %a]%>-"
Controls the format of the status line displayed in the \fCompose menu. This string is similar to `` $status_format'', but has its own set of printf()-like sequences:
total number of attachments
approximate size (in bytes) of the current message
Mutt version string
See the text describing the `` $status_format'' option for more information on how to set `` $compose_format''.