The menu extension plugin contains parameters for you to set what the main and offhand slots are called. The default is just 'Main' and 'Off'. Using longer names like 'Right-hand' make the status scene look a bit squished, but on wider resolutions that would look fine too.
Unless I'm misunderstanding you, and you're actually looking for a way to dynamically name that slot... Like some actors it says 'right' and others it says 'primary'. That's something I can definitely do if you're looking for it.