The 1438156-3: It is a free-hanging (in-line) plug with a latch holder for positive retention when mated to a matching pin header.
What You Need to Know Before Ordering
Contacts are not included with this housing — you must order the matching female socket crimp terminals separately. The single-row, 6-position layout keeps the harness narrow; the latch holder adds vibration resistance over a simple friction lock. Mating half is a 6-position, 0.100-inch pitch pin header with a compatible latch ramp.