Asus KGNH-D16 - Manual (Page 46)

2-28 Chapter 2: Hardware information
2. USB connectors (5-1 pin USB3; A-Type USB4)
These connectors are for USB 2.0 ports. Connect the USB module cables
to connectors USB3, then install the modules to a slot opening at the
back of the system chassis. These USB connectors comply with USB 2.0
specification that supports up to 480 Mbps connection speed.
3. Thermal sensor cable connectors (3-pin TR1, TR2)
These connectors are for temperature monitoring. Connect the thermal
sensor cables to these connectors and place the other ends to the devices,
which you want to monitor temperature.