The author doesn't appear to know the difference between MMC (MIDI transport control) and MCC (Arturia software):
Page 128 (and page 140)
9.1.5.4. Transport Send
This setting allows you to set whether and how the KeyStep Pro will transmit transport commands such as Stop, Rec and Play. It can either be OFF, MCC (meaning that the KeyStep Pro will use the setting currently stored in the MIDI Control Center) or use the current realtime setting.
9.1.5.5. Transport Receive
This setting allows you to set whether and how the KeyStep Pro will respond to transport commands it receives over MIDI. It can either be OFF, MCC (meaning that the KeyStep Pro will use the setting currently stored in the MIDI Control Center) or use the current realtime setting.
(my emphasis in italic)