Why connect a connector to Vcc

Hi,

Could somebody tell me why on connector JP1 in this schematic pin 1 is connected to VCC?

schematic

Is it required? Good practice? Or some other reason?

Thanks

Maybe like the Vin pin on an Uno, it's a means of providing a source of the input voltage as provided at the jack, back to the outside world?

You might want to use it to power a sensor, as the rest of the pins on that connector go to the analogue pins (or GND).

Thanks

You absolutely want it to provide the analog reference voltage, so your sensor can be ratiometric.