The Pixhawk connector standard is intended for in-vehicle, cross-PCB use. It uses the JST GH series, which offers a latch lock mechanism at a small size and a very competitive cost, and it's used across multiple Pixhawk Standards as the default connector.
The Pixhawk Autopilot Connector Standard is documented as part of the Pixhawk Reference Standards and is referred to as the official Pixhawk DS-009 Standard, the latest up to date version can be found on GitHub.
* DS-009 Pixhawk Connector Standard (GitHub)
Note, this was originally referred to as the “Dronecode Autopilot Connector Standard.”