I don't think that it is a Molex-brand connector, but rather a 0.1" spacing pin header plug.
The Molex 2510 has the same pin spacing, and is the common keyed Molex connector used on stepper motors:
http://www.tridprinting.com/Electronics/#3D-Printer-Connectors-Harnesses-Crimps
The Molex 2510 has the same pin spacing, and is the common keyed Molex connector used on stepper motors:
http://www.tridprinting.com/Electronics/#3D-Printer-Connectors-Harnesses-Crimps